Save for a few exceptions, yellow bolts these days are not Cadmium plated because that's a heavy metal, they are yellow zinc as mentioned. Think we should have tested them more like how they do in labs? That info is already easily found, we're using these how people in our jobs might. It's also *IMPORTANT* to understand we're yielding these bolts, because its fun and we wanted to see them fail and where. But the climb up the curve is where they should be used, not near at or past the crest because that's when they are stretched and toast. These values drop when using an equally low grade nut, but we're usually threading into parts like a steering knuckle. Not an opposing nut, so just eliminating variables. We keep bolt trays like Class 8.8: amzn.to/37PtUnD and Grade 8: amzn.to/3Cu6sq3 pretty close by when working on stuff around here. And they make flange head sets for automotive: amzn.to/3vqw5XO Has saved my bacon a number of times! What else do you want to see tested?
There's so many different grades and styles of fasteners out there you could probably do a whole other video. Allthread, Structural bolts, chrome molly, and lots of special application stuff like custom age or cryo treated. In heavy industry we come across a lot of weird specialized stuff that you probably couldn't find unless lifted off a job. Thanks guys it's always interesting.
John Cadogan has a few videos on high tensile bolts, how they behave and the science/engineering behind them. Might be worth a watch and seeing how that information plays into your tests here
Great video. I work at a heading shop that makes automotive fasteners and have always been curious about this kind of info. If you are looking for more to test let me know
@@andy2108if you buy something from their store, or buy access to it off etsy (iirc it's ~$15), you get access to every single spreadsheet they have made, forever
Fantastic video. Very interesting. I have a few comments from the perspective on an engineer. 1:50 - 18/8 is a stainless steel alloy, not a grade of bolt. It also called 304, or A2. It comes in its own three different strength classes - A2-50, A2-70 and A2-80. On metric fasteners this info is often stamped on the head. This steel can't be heat treated, as it doesn't have any carbon content (other than as impurities). The different strength classes are achieved through cold working the steel in this case. 8:36 - Grade 8 / 10.9 is always made from medium carbon (~0.4% C) alloy steel, quenched and tempered, never plain carbon steel. This is a requirement of the SAE/ASTM/ISO/DIN fastener standards. Plain medium carbon steel can't achieve these strength levels. Chromoly 4140 steel and 8640, 8740 are alloys often used for this grade for smaller diameters. For large diameters, 4340 is common. 11:10 - It is worth noting that metric 12.9 and ASTM A574 are standardized classes, but the so called equivalent "grade 9", as well as the bowmalloy are not (they are a product of some manufacturer that does not have to meet any legal criteria behind the manufacturer's promises). Therefore the last two will not be found in any product that needs to meet certifications. 17:45 - Regarding your question about the recommended torque specs, these torque figures are not really related to the maximum that a bolt can live with. Instead, they are calculated to generate a bolt tension/clamping force/preload that is equal to 75% of the bolt's proof strength. This guarantees reusability of the bolt after disassembly. The reason for it is that torque is a pretty poor proxy for preload - even among seemingly identical bolts torqued to the same spec, there is a +-30% variance in the generated preload. To make sure that a bolt does not yield, it has to stay below its proof strength. Hence if we calculate torque for 75% proof, and the natural bolt variance can mean that for some fasteners this will actually be 30% higher, we then get 0.75x1.3 = 98% proof strength, so even outliers won't deform and the bolts can all be reused. In a permanent assembly, where fastener reusability is not a factor, the guideline is to use a torque calculated for 90% proof strength. Most bolts will not deform under this preload, but some will and will have to be replaced if it's ever disassembled. If the engineer wants to use even more of the bolt's strength, he has to rely on more accurate methods than a torque figure, such as a specified degrees of turn from an initial snug position (you may recognize that from engine head bolts), a preload indicating washer, a yield sensing robotic wrench, or specified bolt elongation. Regarding the failure point from torquing the bolt, it's not really something that can be usefully specified, both due to the aforementioned huge variability in torque, but mostly because the torque-preload relationship ceases to be linear once the bolt begins to yield. Finally, in this specific video (not your usual impact tests), a better methodology would be to provide the dyno results as the gauge's direct reading of clamping force, instead of calibrating for torque, because A. bolts are not chosen by the engineer to meet a torque figure, they are chosen to create some clamping force and the torque is calculated to generate this force. This torque is very different if the bolt is dry, oiled, greased, cadmium plated or used with anti seize, but the clamping force is the same. B. You have to calibrate the dyno for every single bolt you test even if they're all the same size, due to the torque variability especially with unlubricated bolts. C. Once a bolt starts to yield the multiplier constant in your digital gauge no longer converts the measured force to torque correctly, as torque no longer varies linearly with more tension. Once again, this was a very interesting video to watch. If you ever do it again with a measurement of the force it would be very interesting to compare the ultimate force you get with the grade specifications. Should be essentially the same as a tensile test, and the forces should match or slightly exceed the specs.
Thanks so much for the clarity. It was hard to listen and watch some of this because some of the info was so wrong. Still worth watching, as it hard to find good comparison testing of bolts
I'm thinking we're on some of the same committees. Your points are spot-on and it is generous of you to take the time to clarify some important points for everyone here. I would add to your comments on "18-8 Stainless" that the term '18-8' is not a specification but merely jargon. If one wishes to know what they are buying in a stainless steel fastener, then one needs to refer to a standard, and at times within that standard, a specific alloy or alloy group. ASTM F593 Type 304 for example. "18-8" merely refers to any steel with roughly 18% chrome and 8% nickel content. Since there is no standard for '18-8' one will end up getting whatever is cheapest presently. This is often 302HQ, XM7, or 303SE. Again without referring to a standard one could get any of these or something completely diffferent. "Stainless Steel" is a confusing term in itself. The material origininated in Germany, back when alloys were trademarked if not patented. Early users of stainless steels included designers of skyscrapers -- who used it on the facades of the Chrysler Building (1930) and the Empire State Building (1931). People are often dissappointed in stainless steel when it . . . . well . . . stains. This can certainly happen with Type 302, 303, 304 --- especially if passivation is not performed. Carbides on the surface left by tools used to form the parts can readily discolor the fasteners when exposed to moisture. Type 316 is the go-to for (consumer) marine applications. Navy fastener engineers (and subsea in particular) are the global experts in stainless steel and non ferrous alloys used to make fasteners for military ships. Take-away: Choose your stainless steel alloy. Reference a standard. Don't simply accept '18-8' as meaning anything.
ARP uses a variety of different materials, but below is a selection that you might find for head studs. (1 ksi is just 1000 psi) ARP: 8740: 180 - 210ksi ARP2000: 220ksi Custom Age 625+: 260-280ksi Factory LS metric 10.9 head bolt: 151ksi This isn't completely apples to apples, as you'll get a little bit of extra clamping force out of the factory bolt by using the torque-to-yield procedure.
@@fastindy What people don't realize is that you don't get anything additional from the stud if you don't tighten them further to the point where they're providing additional clamp load then the factory headbolt. The modulus of steel is the same, the only way this works as a performance increase is with more preload.
Interesting video. I’m a metallurgist and used to operate an accredited fastner testing laboratory. Nuts and bolts are a complicated subject. The way they are installed plays a huge role in how a threaded connection performs.
Spoken like a bolt manufacturer, always blaming the user for poor installation or misapplication. Just kidding, I'm an old QA manager reminiscing about the little daily wars.
Agreed Ted. I've seen grade 8 bolts snapped from hand tightening because a misaligned assembly caused bending of the bolt. Tension, torsion and bending combined can overwhelm a sturdy fastener.
One could add, that the markings in the metric system actually make a lot of sense and tell you about the physical properties of the bolt. 10.9 for example: the first number (10) multiplied by 100 gives you the tensile strength of the bolt (1000 N/mm²). Multiply that by the second number (.9) and you get the yield strength of it (900 N/mm²). Simple as that.
It would be awesome if it was that simple. That would make 8.8 bolts have the same tensile and yield strength which could get pretty scary in practice. Actually the second number is a factor that is 10x the ratio between the nominal yield stress and the nominal tensile stress. Also the conversion from newton/square millimeters (N/mm²) to MPa is times 1. They are scaled the same, so no need for unit conversion unless you need SI base units instead of derived units.
Metric always makes a lot more sense than crappy inch luckily no one use outside of the US. In the US and CA, it is a nightmare because on the same truck, car etc... you find a mix of metric, UNC (the worst) and UNF (some easily confused with metric). A waste of money too !
I've used tons of stainless bolts for bolting together RF transmission lines that have bronze flanges with o-rings that have to bolt together to make an air tight seal but the also not corrode or react in the open air environment for 20 plus years. Biggest issue with stainless is galling, but they are quite durable and you don't have to worry about a rusted nut not coming off years later. The bolts we use come with a wax coating so they actually have a bit of a grey hue to them instead of being super shiny as the wax helps prevent galling as you tighten them.
I'm a boat builder and agree with you 100% . I've had the most trouble with trying to remove stainless nylocks, I think small nylon fragments wedge into the threads and increase the forces on the threads causing them to cold weld.
Sounds like EIA flanges. I've installed many of those (from 7/8" to 6-1/8"), on FM broadcast antennas and transmitters, both on the ground and in the air. There's nothing like being high up on a radio tower, discovering that the last guy over-tightened and galled the stainless bolts on some rigid transmission line sections, then struggling to shear them in half with the tools you have on hand. Then one of the bolts lets go suddenly, and you drop your wrench or ratchet... not that I'm bitter or anything.
@@Joel_E yeah the flanges I deal with are for TV broadcast in the six to 9 inch versions. Mostly made by Dielectric. 1500 to 1900 feet off the ground doesn't give a lot of forgiveness for dropped tools!
I build and service large fuel tanks for oil companies. Whenever replacing a seal on these tanks is pretty much guaranteed that I'm going to be replacing thousands of stainless ⁹/16 bolts due to galling..
I used to work as a maintenance engineer in two local chemical plants, we used some large steel “bogies”, which weighed several tonnes each. The shelves were held into the bogies using ¼ unc bolts at one of the plants and M6 cap head bolts at the other plant. The cap head bolts (12.9) used to shear off for fun, yet the regular ¼ unc bolts never did. As for stainless bolts- they are a real pain in the backside, especially when they gall up and cannot be cut off with the gas axe!
If you use a 300 series SS bolt and nut, you’re in trouble. If you use a 300 series bolt and a 400 series nut(or vise versa), you’ll be ok. Another option is a SS bolt and a carbon steel nut. Dissimilar metals is the trick.
Great video. I am an engineer and have known what the outcomes should have been for a long time, but I rarely get to see heads up testing like this. Always neat to see the real world line up with the specifications that I use day to day. When they don't line up, trouble happens. :(
I broke a 10.9 OEM Ford bolt while trying to hit 129ft pounds. Shocked the hell out of me, and caused an 8hr recovery mission to remove the stud. Bought a generic bolt that has L8 on the head from Lowe's to hold me over. Deathly afraid of it breaking, so I watched this video then immediately ordered a grade 8 from Lowe's. Thank you for the help!
I used to work for Bowman. They are the company who originally created the Bowmalloy fasteners. They were bought by the Barnes Group and then MSC. They kept the name due to industry recognition. For a time, these were made in China and almost cost Bowmally their reputation. I believe they have been brought back to domestic production now.
And the 'illuminati' symbol is the Associated Spring logo because Barnes owns Associated Spring and the bolts were sold to distributors (like MSC) through their Associated Spring Raymond brand.
Good company. Knew your bolting guys very well. You guys used to source Bowmalloy at Lake Erie Screw Company (then in Cleveland) when the Wasmer family ran it. That was a classy operation -- on par with the best in Germany or Japan.
Which is a function of China having a tendency to say an alloy is someting it's not. China has great engineers. If they created alloys with the same demanding specs we do, they could of course produce bolts (or any metal item) with the exact same high quality the U.S. or Germany does. Throwing a bunch of scrap metal into a furnace and calling the resulting alloy "Grade 8" (or whatever) is the problem. They could produce quality if they wanted to.
Metric stainless fasteners are marked A2 or A4 for the material type (with A4 being higher corrosion resistant in salt water and chlorinated environments) and a number (50,70,80) that indicates its strength class, with 80 being equivalent to 8.8 As for the relationship between clamping force, torque, load, and so forth, there's whole engineering books about it, so the information exists, it might just not be explained in simple form anywhere easy to find. Odd. :) It would explain the amount of bolt abuse you see people do. In short, the bolt fastening torque is mostly set to optimize clamping force. Clamping force makes sure that shear loads are absorbed by friction between the clamped faces, and that cyclical loading doesn't fatigue the bolt or joint. A loose bolt would shear off or fatigue, or rattle around and damage the hole, where a properly tightened one would not. An over tightened one could snap from being over tightened alone, or could damage whatever its clamping.
As for clamping force, what you mention is one part of it. To expand, the torque determined for a bolt is derived from the clamping force needed to maintain a sufficiently ridged connection. This is determined by the connection use, like clamping a pressure vessel, sealing a gasket, or affixing two solid objects together. Generally, you would choose the bolt grade based off of what your clamping force needs to be from the design criteria, not a tightening torque to prevent bolt damage. A loose bolt would also wallow the bolt holes or damage the clamped material, it most likely would not shear unless shearing impacts were applied, although a loose bolt will fatigue faster generally
For sure yeah, I think I probably could have worded my post a little clearer. Those design calculations also often show why multiple smaller bolts are better than one single big one, the clamping force is distributed much more evenly. I think the times I've seen bolts shear clean off were indeed shock loaded in shear, which would have been find if they were tightened to spec. Also, seeing people use loose bolts as hinge pins and shear loading the threads just really rustles my jimmies. At least use a shank bolt (-properly). Never mind actual proper ways to make bolted hinges.
Correct, very important to choose the right grade of corrosion resistant bolts (A2 or A4) with regards of the environment where they are used. A2 is good enough in fresh water, but will be destroyed in salt water over time. A4 is more expensive and contains additional Molybdenium in the alloy, hence more suited for salt water (or chlorinated) environment.
Tightening torque is based on 66%-75% of the tensile loaded yield strength, and depending on who is doing the calculating for that factor of safety. It has to do with avoiding fatigue, which is based on yield. Adding an axial load onto the bolt adds some tension and reduces some of the clamping load until the clamped pieces separate. For most bolts, this ratio is 0.33 * load applied added to the bolt, or less. I believe steel is usually .2-.25. This ratio of force applied is part of what makes proper torque avoid fatigue. If the total load of the bolt varies by 5% and doesn't yield instead of varying by 50% or more, that bolt will stand up better to cyclical loading. As much as I like your videos, this particular test doesn't mean much. Torque is heavily influenced by the lubricant you use. Molykote P-37 generally has the most consistent results across materials. Unlubricated threads vary widely between material and coatings, not grade 5 to 8 but steel to stainless or Monel or K-Monel. And a comment on grade 8 and harder alloy steels (>34 HRC or >150 ksi UTS). You should avoid any kind of zinc plating because it actually increases susceptibility to hydrogen embrittlement, which is a science term that means a bolt can break at 30% the rated load from environmental conditions. There is some debate where the exact cutoff is, but the toughest alloy bolts can easily lose a lot of their strength from a coating, sometimes before it is ever installed if it was done wrong (See San Francisco Bay Bridge failure where hot dipped galvanized bolts broke throughout) For anyone interested, Fastenal has some great explanations of all of this: www.fastenal.com/en/69/bolted-joint-design TL;DR. Bolt tension and reliability has a lot of factors and unlubricated torque runs til failure look nice but unfortunately don't really tell you much from a scientific point of view without concentrating on where they yield and controlling other factors by using a high quality lubricant, like Molykote P-37 or similar.
You're completely incorrect about the zinc plating. This is what I do for a living I make and test fasteners by the billions with a B. Zinc chromate plating is an extremely common surface finish. Every single lot is baked out for several hours after the plating process to drive any hydrogen out of the steel. Although in recent testing it's shown that anything under 34ish HRC is not susceptible to hydrogen embrittlement it's still done because it's written into the ISO and individual OE standards. In addition to that Fastenal doesn't make a single fastener on their own, everything that they produce or sell comes from an established fastener supplier. They are not in any way shape or form a technical expert, they are just middleman distributors.
@@otm646 According to ISO TR 20491 the cutoff is RC39. Also ASTM F1941 requires 12 hours of baking, not just a couple. And Fastenal does actually own several fastener manufacturers.
There are tougher bolts out there. NAS8906 go to 220kpsi and NAS8907 go to 260kpsi. They're used in aerospace framing and are single point turned rather than rolled on a screw machine, and have a tighter class of fit than normal threads. You have to go to a dedicated screw house for those, and are the last stop before custom designed solutions, like special alloys and ground threads. Most applications care more about performance at temperature and corrosion rather than just straight performance though, which is why A286 and inconel screws are also a thing.
You might know a thing or thee. Haha drives me nuts when people ask for the strongest bolts possible (a325 gr55/105 or some shit) because they saw marking on a bolt head in a building. Like mofo, your gar away from the "strongest". And what strong you want.
Perhaps a test of thread lube? Grab a bunch of those grade 8 bolts and slather them in various thread treatments... ARP ultra, motor oil, a few greases, anti-sieze, threadlock, etc. You could test torque consistency and overall torque before failure.
@trashcanmucous5153 Hmm, that is a good question. My first thought would be some anti-seize, as that its purpose. But plastic doesn't weld to metal, it can only melt or deform like clay. Is it feasible to add a material in between the parts like a film, wax paper, or bushing?
Grade 1 and 2 are fine for most wood fastening applications, since the wood will fail before the bolt. The carriage bolts you are testing are a good example - if building a wood carriage, just use grade 1. Many people assume a higher grade bolt it better in all applications. This is incorrect. Some bolts are intended to fail to prevent more severe damage. Some bolts are better at shock loads than others. For instance, bolts on suspensions are intentionally not high grade, because higher hardness is usually more brittle, and the impacts in the suspension mean that high grade fasteners may snap during use. Lower grades will stretch, and that stretching and loosening of the fastener can be accommodated in the design, since the major loads can be designed in shear and not in tension. The torque applied to the fasteners is also sometimes more critical than people assume, and too tight can often be a very big compromise to the fastener. Preloading the tension or creating additional stretch reduces the capability of the fastener in tension and in shear. Each application presents a window of proper torque for the fastener, including whether clamping force is required or just sufficient force to prevent the fastener from backing off. These windows also depend a lot on the fastener grade and thread configuration.
Very good explanation The amount a bolt will stretch and return to its original size without fatigue is known as the elastic range, the harder the material the shorter the range.
14:04 FYI, that's just the Bowman Distribution company logo (now owned by Barnes) and doesn't necessarily mean it's their proprietary high strength alloy. I've got an entire bolt bin of old grade 5 bolts with the Bowman logo on the head. Great video as always!
Years back I had to replace 288 1" bolts that were holding a ski lift together because they were counterfeit. They had been in use for 35 years and none of them had ever failed and none of them broke on removal even with about 10 coats of paint on them and rust. A325 bolts and A563 nuts were all torqued to spec in a 3 step process 50-80 feet up the towers.
Better safe than sorry. Thank you for doing whats right to ensure others safety. Also, thanks to whomever noticed the wrong fasteners and demanded them replaced. Standards exist for a reason.
@@jason86768 , @NFR Computers It was the elevating device authority in my area that brought it to our attention. The reason the counterfeit bolts had been supplied was a weird story that had mob ties. 3 of the prior lift maintenance managers had ignored the warnings and when I took the job I inherited a stack of papers outlining safety infractions that were ignored for years. My signature on the daily logs was enough of an excuse for me to take action. Sadly since I left that job ,all things safety and common sense related have been ignored. While at the facility this year I brought up many safety problems with several board members and was told to mind my own business. They will eventually hurt or kill someone.
One thing I would like you to try.. apply some anti seize to the stainless before it's run. reason being stainless binds up when heavily impacted. the antiseize keeps it threading freely.
When I took the plow mount off my truck I found out the shop that installed it used stainless bolts to fasten the two pieces together. Was shocked to find 304 stainless was able to withstand the punishment of finding hidden obstacles albeit they were large 5/8 bolts. I would suspect smaller diameter bolts wouldn't fare so well. Nice to see an actual test comparing them to steel counterparts. McMaster-Carr carries an extreme strength stainless that is supposedly comparable to grade 9, would like to see that compared to 304/316 and 18-8.
Very informative and well put together video. I went back to college around 20 years ago to finish my engineering degree. I always found testing and comparing similar items to be quite fascinating. Nope, I'm 54 this year and still haven't finished my engineering degree. In the meantime I've acquired close to a dozen different degrees/ licenses. Quite honestly, it won't make an ounce of difference if I finish my engineering or not. In Canada, once you have reached 65 years old, you can return to college at zero cost. Maybe I will finish my engineering then. I just hate not finishing something that I started.
Thanks for the testing. I have always used minimum grade 5 bolts and mostly use grade 8. I avoid grade 2 or below as much as possible. Glad to see your testing results showed the difference. Appreciate your videos.
One thing I noticed, when I would tighten stainless steel bolts with stainless nuts, very tight, is the threads tend to "gaul" and seize up. Great test THANKS
Doing a boat motor mount that has to hold a 170 lb 25 hp motor. It is cantilevered 28" out off the boat due to needing to clear a swim platform. Glad that stainless steel bolt was slightly better then the grade 5. I am using 1/2 stainless bolts just like this for holding that motor mount to the transom. Now all I gotta do is engineer that transom reinforcement properly on the back side and I should be good to go. Thanks so much for doing this video. I feel much better now about those stainless bolts. The motor mount is 6061 12x13, 3/4 thick plate with 6061 2x6x.250 tube between the transom plate and the motor plate, it is tig welded with 300 amps by a guy who does many hundreds of feet of tig welds per year. Why that aluminum plate and tube? It is just what I could scrounge up.
Yes, stainless steel plate is very expensive, so it's a money saver using aluminum. 6061 - T6 is hardened aluminum, but as long as your not near salt water it will last. Retired welder.
This is cool and especially interested to see how the 304 stainless bolt does. Many think it's perfect due to corrosion resistance compared to normal steel and strong stainless but I believe they are probably below grade 5 strength due to brittle nature of stainless. I will see if I'm right as I watch!
Ok watched it and I gotta say I'm surprised by the stainless result! I agree that I've been confused by spec sheets and avoided stainless fasteners in more important areas due to fears of overall strength - I usually figured less than grade 5. But this test showed it much closer. Id imagine the application still will matter such as static fastening vs shear forces on the bolt attachment. Still neat data so thank you!
I agree. Did better than expected but also it's too wishy washy of a distinction to assume grade 5 equivalent. Shear strength shows a wide range of acceptability.
@@TorqueTestChannel Just an FYI, not all 18/8 alloys are 304, and not all 304 alloys are 18/8. Type 304 is 18-20% chromium, and 8-12% nickle, but also maximum 2% manganese, 1% silicon, 0.045% phosphorus, 0.03% sulfur, and 0.08% carbon. Generally 18-8 bolts are cheaper/worst quality than a 304, but can be stronger due to carbon content, especially in forged fasteners. Also 18-8/304 are only freshwater compatible, you need 316 for true saltwater resistance. Though even 316 can rapidly corrode in anaerobic situations due to crevice corrosion. The molybdenum in 316 makes the fasteners tougher than 304, but softer. So higher yield, lower tensile. Also using stainless isn't recommend for any torqued application is the threads galling. So its easy to torque the fastener correctly, but have little to no clamping force.
thanks buddy. I put up a gantry crane and one end is supported by carriage bolts. Didn't realize their lack of effectiveness as a fastener until your enlightening video. did wonder about their strength rating though. Didn't know about the grade 1 rating. Crazy, but I thought grade 2 was the bottom of the barrel. and I come from an industrial background! We never used anything less than grade 2, the flat heads, or stainless, but mostly grade 5 or higher rating. The other end of the gantry is supported by grade 8 bolts though. Now I only have a 1 and 1/2 ton chain fall on the beam, but you can be sure I will change out the carriage bolts for grade 8. As an aside the gantry is 18' long with 12 carriage bolts scattered from center to one end and another 12 grade 8 bolts scattered from center to the other end. I believe in over doing it in the name of safety. Don't want anyone getting hurt.
The vortex pattern of every sheered bolt tells a story of heavy lateral torque as well as some tensile loads, and remember these books are graded for tensile loads, not lateral torque load, but very cool video on bolt strength!! The best way to test these bolts is to load the nut to a common ft/lb then hang weight from the bolt 🔩 to achieve a purely tensile load.
There is no way you could be too Loong in making a informative video. I learn as much as I need to know from your videos as I do from Project Farm and belts and Boxes. Thank you for helping me understand Bolt grades.
really interesting seeing these torque values with impact guns. most high torque applications are done with hydraulic wrenches or hydraulic bolt tensioners which are not comparable in any way to impact guns. good work on this channel. consistently impressed with the stuff i'd like to know but have no intention of going through the effort to find out myself.
Love to see bolt specs finally tested! This is particularly valuable info for a home gamer without a torque testing setup to be able to test their impacts at home with some degree of accuracy, my method has always been to set it to max power, stick the bolt/nut in a vise and see how high a grade/size it’s able to break or strip the threads out of
Two major flaws here that are likely to mislead interpretation. The first issue is "18-8" is not a specific alloy, it just designates a generic stainless with a minimum 18% chrome and 8% nickle content, but there are many alloys that contain that amount of Cr and Ni.(Stainlesses also have other engineering considerations such as pitting corrosion and corrosion fatigue which do not effect non-stainless in certain corrosion environments.) The second and bigger issue is not using a standard EP thread lube. By standard I mostly mean using the same grease for all tests but preferably a lube meant for the task eg ARP sells one. EP for screw threads is usually a solid additive like moly or graphite as opposed to the surface active additives more common in EP gear lube. This is especially important for austentic stainless which are very prone to galling (microwelding and plastic surface deformation) especially when used with a matching stainless nut. (As is normal because dissimilar metals in contact will corrode much faster.) The standardized lube takes out the surface finish variable(major) and overall reduces the torque component of stress relative to axial stress. Surface finish and lube choices can change the ideal torque for a fastener by 70% Non-EP lubes like motor-oil are only consistent at low torques on low grade bolts, they can't maintain a significant separation film between the metals under high pressures at these low speeds. (High speeds suitable to form sufficient dynamic film strength would be like 2000rpm+ at this small diameter and high pressure.)
Great video. It's only telling part of the story(arguably the most interesting part). Different grades have different applications based on whether they bend or stretch, or just snap. The Bowmalloy is a very unique bolt. They are actually manufactured by Barnes Inc. And commonly used by Barnes Aerospace. The head marking is actually a spring from the Barnes logo. Bowmalloy is designed to retain the hardness and tensile strength of a grade 8 bolt, but bend without snapping. They were designed to be used in the aerospace and space programs where vibrations were a concern. You can take a Bowmallow bolt, bend it in half without it snapping.
I love these straight forward videos without the fluff and thirsty requests to “like and subscribe” and unwanted advertising. Just on that alone, you got a like, and a new subscriber.
This was a great idea for a video from you guys. Thanks for all that you guys do! Also, you mention being car dudes, and I'm curious what you guys drive.
I was always told when I was growing up that the purpose of bolt grades wasn't for tension but for their shear resistance. We would use grade 5 bolts as a sort of fuse for our grain augers to keep a potential clog or other fault issue from destroying the internal auger. I would hear tales of my grandad shearing a G5 bolt and swapping in a G8 to get the last of the load finished, but at the expense of completely mangling the auger with the extra torque applied from the shear resistance of the G8. We had a specific box of "cheese" bolts for our smallest augers as even G5 would be too strong to fail under a fault.
I spent 6 years working in Aerospace, I'm curious how aerospace grade bolts would compare. Might be worth a video, I know the prices on these bolts were ridiculously expensive, would be funny for your community to lose their minds over the prices of each
You can snag them surplus quite reasonably. Found some for a few bucks a piece to repair an industrial grandulator. The blade mount bolts were very similar in spec to the aerospace bolts except they had a torx type cap instead of the hex cap. Was for a Cumberland B60 grandulator machine. 🤓
We use the Bowmalloy bolts at work for adjusting clamping force on vibrating material handling equipment(which is a great way to make small adjustments to the vibration), you really need to use torque wrenches with them. Unlike grade 8, it's very hard to tell by feel if they are about to yield. And they are very hard to drill out and remove from the equipment once they break off.
Would be interesting to see the same test performed by hand instead using an impact. Also why no lube? Lube shouldn't impact the clamping force or material properties of the bolt. You would just need less torque to reach the failure point.
Lubrication dramatically changes the clamping force at a given torque. In a joint with a lot of friction, most of the torque applied goes into overcoming that friction. Add lubrication and a lot more of the torque actually goes into advancing the fastener and generating clamp.
@@danieljackheck That's is exactly what I am saying. The peaking clamping force won't change because that is a function of the yield strength of the bolt, but you will need a lot less torque to get there.
Great video! 35 year industrial maintenance man and engineer here, and I have been down the rabbit hole of bolt ratings for certain high stress applications many a time. 18-8 isn't a bolt rating - it's another type of Stainless steel, like 316 or 301 or 304. So when you see it on a bolt head, it's designating that it's Stainless and which type of Stainless. Different Stainless steels have different corrosion and magnetic properties, and in many applications those are what matter the most over torque, toughness, and hardness. Many Stainless bolts are very close in the torque, toughness, and hardness ratings, so the differing properties of the different kinds of Stainless tend to come into play.
Lol we showed you how to ruin them. With a grade 9 opposing nut as well. Use the charts to determine where it's still within plastic deformation and would go back to being a happy bolt (the climb up) and where it's no longer a happy bolt (peak and cresting over).
Just a comment on your conversion from pressure to torque: this is dependent on the friction coefficient in the thread and between washer and nut. So for different surface treatments of the bolt there will be a different conversion factors. Also, your recommended torque should ensure that you don't exceed 90% of the bolt's yield strength when tightening. When your pressure curve flattens, you already exceeded the yield strength of the bolt
One of my first experiences with 1 time use bolts was on a flywheel to crank bolt on a Nissan 240sx. When re torquing the bolt it snapped pretty quick. Very brittle. Nissan had them in stock for $6 a piece like 20 years ago. My buddy says BMW uses a fair amount of 1 time use aluminum bolts. Save a little weight.
One time use bolts= head bolts for Diesel engines...those are "stretch bolts" They only stretch once.VW had them with a Torx socket head. Can reuse them -just not to tighten down heads. $6 each & there were 10 of them.
I work in steel fabrication. We fabricate the steel for wherehouses and schools. A307 bolts are bottom of the barrel but are used in nearly building for non-inportant pieces. A325N and A325TC bolts are the ones that hold the stairs, beams and tubes together. Pretty much everything structural
In my experience as a mechanic/ hobby fabricator stainless bolts snap or stretch far earlier than anything else. I won't use then unless it's for a low torque submerged application.
I think it depends on he manufactura and application they were intended for. I have experience with true stainless exhaust bolts and nuts an they love ceramic paste because the threads wear out quickly in compariso but they do not snap or stretch. They are between 8.8 than 5.8 but closer to the first.
I was told not to use stainless hardware on my beadlocks. a tone of people said they were weak and would snap so I put one in a hole in a metal table and bent it with a hammer. they are strong enough for what I want to use them for. glad to see you confirm that hard to find info or test on them
I'm not sure most people understand why studs are preferred over bolts when it comes to things like the heads on an engine. Interestingly the answer is right there in the name of your channel, torque. Studs yield more consistent and accurate results over plain old bolts. I don't know why it took me so long to come across your channel but, I love it. The information you provide is clear and useful. After watching the first video I immediately subscribed. Keep up the great work my friends.
Hey thanks! Yes, consistent bolt tension is the name of the game. Input torque is sort of a crude way to get to bolt tension, but a fixed stud with nut is the best way to get there, especially with a known K value (lube)
My old boss wanted to put in used regular non grade bolts in a man lifts castor wheels. They would put wedges in the lift leg sensors to trick the machine into thinking the legs were down and in place and all the weight would be on the wheels, that way they didn't have to mess with the legs and lock out system when they did light changes in the gyms. They just wanted to roll a guy 30 feet up from light to light and save time!! I told him to go to hell and I wouldn't be going in it ever again. I was 3 weeks in that job, but I couldn't let him do that and kill me or someone else.. after that I was on the gotta go list and only made it over a year before getting fired over "budget" cuts..
Loved to watch this video, however I have a small point. 9:40 The yield point of a bolt is not when it starts losing tension (graph line goes down again) but it is the transition between the steep uphill and the flat lining. In technical terms the yield point is described as the amount of stress a material can take where is plastically elongates 0.2% over its original length measured after unloading. What you were reffering to is (close to) the ultimate tensile strength. UTS is a measure of stress which is force over area. The cross sectional area changes as a bolt gets stretched so the UTS of the material actually gets reached after the curve goes down again in terms of pure beans. In material stress tests it's critical to measure the area of the snapped off samples to determine the actual stress in the broken region. Rant over, keep up the great videos!
Titanium is actually very brittle. You wack the typical racing pedal with a 3lb mallet, it'll shear clean off. I'm also not sure how much titanium is used in these applications, by the way. You'd have to test specific products. It's quite common for commercial products to be electro plated or finished with a metal, and then sold with that branding. It's not a 100% solid product or even an alloy in many cases. A good example of this is cookware. Stainless steel cookware is the name of a finishing, isn't made from any stainless steel. Cast iron isn't solid cast iron. Copper isn't copper. Etc.
No expert but 316L SS is the typical go to alloy for Marine , and other chemical environment applications. 304 SS is a good rain 🌧️ resistant alloy. Great video and thank you for all channel content!
There is an EXCELLENT lecture series on fastener physics that NASA uploaded to youtube from the 90s or something. That's where I learned that lock washers don't do squat! It's phenomenal!
Some background from a BSc student Mechanical Engineering: It is not weird that the hardened bolts fail/shear in the tests with the Thor impact. The hardening makes the metal brittle, whereas the cheap bolts will just stretch. It is like comparing a brittle cookie to a flexible rubber band. So for their application (high strength fixing) they are great, because the rated tightening torque is well below failure point and these bolts will withstand a lot more in their lives. And the "weak" bolts are usefull in applications where only low strength is required (in cost considerarion), or even in flex/movement compliant design (wood construction for example) . Very interesting to see this theory applied! I like your videos!
Great test of coarse thread bolts. The same test with fine thread bolts and comparing to the coarse thread bolts would be informative. Fine threads are much stronger. In many cases, the bolt is using the sheer strength of the shaft more than the clamping strength of the threads.
I understand SAE nominal same size "course" thread bolts have a smaller minimum cross section thickness than "fine" thread ones giving a stronger tensile strength. (In the same grade) the course thread valleys are deeper.
Can we all just stop to appreciate the fact the availability and common use of these bolts at their price is amazing? 100 years ago this would be unheard-of.
The problem with using stainless bolts is that if you over tighten them, the threads of the bolt and nut can gall together and are nearly impossible to remove without cutting it off
That was...awesome! Thank you! Any chance you can do something like deck/wood screws? Im dying to know if some of the stuff is worth the money. Thanks!
@@kjdude8765 I've seen the Project Farm video on them, I'll have to check out Stumpy's. I realize now I wasn't super clear in my comment, I said deck/wood screws, but I was thinking the larger stuff like the standard lag screws/bolts, timberlocks, GRX Lag replacements, etc. For instance GRX claims their thinner lag screw replacements are stronger than the much thicker standard lag screws/bolts. I'd be curious if their claims are true, and if they are, how much stronger are they? Just an idea, maybe this is more suited for Project Farm as a follow up video to the first one on wood screws.
@@justtime6736 I generally do. My asks are generally around comparisons of more expensive items, the ones I really want detailed information on to make proper buying decisions. It'd be nice if he would mix more of that stuff in. At least do 1 or 2 for seasonal stuff, for each season. Eh...but I'll take what I can get, bit drivers it is...lol!
I've worked with a lot od stainless steel fasteners in food processing equipment. Mainly for corrosion resistance, not so much for strength. Lots of 'Ny-lock' nuts there, not actually for any real 'locking' ability, but for their resistance to falling off if they get loose, and damaging equipment. Then I've also spent a lot of time working on machine-tools, and heavy equipment. Lots of 'Allen' head fasteners, they are usually in recessed holes where you don't want a lot of material removed, or more often clearance issues, so you have the head of the Allen bolts in holes recessed to just a few thousands of an inch clearance.
I'd love to see a shear comparison if you have the setup to accommodate. Particularly interesting would be under load or torqued to the recommended value. If the shank diameter is the same across grades the shear limit may not be (speculation) greatly effected by a loaded or unloaded bolt.
Yay, we're not getting ripped off! If anyone was scratching their heads at the introduction of the 304 bolt at 1:44, in which it was called "non-steel, non-ferrous": 304 _is_ steel, and it _is_ ferrous, being an alloy of 60-something% iron (the rest being a lot of chromium and nickel, plus 11 secret herbs and spices). However most of that iron is in the form of austenite, and austenitic steel is non-magnetic, which I suspect is what they meant to say.
@@Mp57navy I didn't say 304 is non-magnetic, I said the austenitic steel in it is. Steel is never truly homogenous; different ferrous structures crystalize and come out of solution at different times/ temperatures during manufacture. The resulting alloy is never 100% of just one type of cubit-faced crystal. That's why I specified _most_ of the iron in 304 is austenite.
Oh, another thing about stainless bolts. While there's a big temptation to use them on headers (and other exhaust parts) it's not a great idea. As they heat cycle, they loose a lot of their ductility and become brittle. Then they just snap. All it takes is the thermal expansion of the flange, and it can rip it in half.
I just need to correct you on one fact: Socket head cap screws are indeed available in classes lower than 12.9. I have some class 10.9 and some class 8.8.
All right, now try a collated self tapping bugle head modified truss serrated flange lag bolt… 🤣 Great video, we actually have a lot of people buy stainless steel bolts for Parks and Recreation/outdoor applications at the store I work at. I always tell the people that grab the stainless steel bolts that they will break very easy.. they never listen! 😂
Not a problem if they properly lubricate the thread to prevent galling. Hot dip galvanized are fine for wood playsets and furniture. Almost any fastener is strong enough to crush wood fibers.
Structural Engineer and ICC Structural Steel & Bolting Special Inspector who works at nuclear plants. A325s are A325s whether they're being used in a support structure holding up a steam generator at a nuclear generating station or in a pre-engineered metal building for a dollar store. The main difference is the paper trail creating traceability for every bit of that bolts life from raw material to install. _I used A325s as an example, but the same goes for any grade bolt._
Do you mean monel, Inconel and hastelloy? They're favoured for corrosion resistance in very salty applications (think like 304 is for seawater, it doesn't necessarily mean is stronger). But, I agree, it would be cool to see on the charts.
If you do this test again, I would love to see a comparison include 17-4PH and A193 Grade B6 bolts. In the line of work I do we have to use both of these a lot. If you wanted to go all out, ASTM standard A540 has some wild hardware to check out.
On metric rating the first digit is actually the value in Newton (N) times 100 per mm². So 8.x is 800N per mm². So you can calculate the strength on each bolt yourself without looking up a table if you calculate the cross section. The second digit in the metric rating is only indirectly related to strength, it indicates the point where it starts to stretch WITHOUT going back to its original form. So x.8 = 80% of 800 = 640N per mm² it will start to stretch. Also I learned that if you use a "softer" nut you can achieve a higher torque before breaking since the treads can distribute the load over several treads on the nut and not all is concentrated at one point. In fact: Using a harder nut than the bolt is, might be very counter productive. I did not know about the US rating system, it was interesting to see. I like your tests! Please keep doing them 🙂 👍
Great Video, this actually helps me understand now why "factory torque" is important to follow when putting on wheels etc, (Tighter does not always mean better lol) otherwise you could stretch out the threads or snap the bolt etc. Thanks again!
An almost perfect experiment, thank you for sharing. One little critics, you should have considered the length of thread for each bolt. As you know weakness comes from root of the bolt thread and when you apply force on threaded part length of thread and elongation make the difference. Respect from Türkiye
I enjoy watching your tests. I believe they show fair comparisons that give insight into how selections should be made. In regards to the stainless bolts consideration has to be given to the service they are going to be used. My background is with oil tankers. We specified stainless bolts be used on deck and in tanks for corrosion resistance. In general stainless is a good choice. However, we found we had fatigue failures on bolts that were used in areas where there the bolts were exposed to high cyclical loading such as the mounting of hydraulic valve cylinders. Proper alloy selection along with tensile strength needs to be taken into consideration. Another issue with stainless steels is their corrosion resistance. There are significant differences between alloys. Having a stainless bolt does not mean it won't corrode.
Thank you all for the helpful information! Now I know what "grade" bolts to use when I rebuild my LR4 motor. I was confused as to which was better, but this clears up my confusion. I am so grateful for your time and hard work!
Great and useful video, thanks so much! Stainless steel deck screws are far weaker than any steel screws, so I assumed the bolt would be weaker. I had to use a drill with a clutch, my little impact driver kept twisting them off. So that 304 / 18-8 bolt was s surprise.
I like to use a lot of Grade 8 bolts and "Grade 8" Nylock Nuts and especially "Grade 8" (aka hardened), washers b/c the washers don't deform under load/tightening. I find the Yellow zinc coating present on most "Grade 8" stuff to be FAR superior for weather/rust resistance then standard zinc.... I buy them in bulk b/c the cost difference does not seem to be that great over grade 5 (and is sometimes cheaper from one of my suppliers for some reason) They are also often available cheaper than grade 5 zinc in "plain" finish which makes them very easy to weld prep and paint b/c you don't have to strip the zinc off before hand. Grade 5 Plain finish and Yellow Zinc are also available and I often purchase those as a "lower" strength alternative... But unless they are substantially different prices Grade 8 is my go to for anything not requiring stainless or Hot Dipped (I always buy grade 5 hot dipped b/c the ungraded bolts especially carriage bolts seem to be made of "Cheese grade" steel) The quality of the fasteners/threads & finish etc is WAY better then buying the garbage sold in most hardware stores and big box stores and when purchased in bulk are WAY cheaper then that crap.
I use to work in a lumberyard and we would use chains in the winter and they were secured with a carabiner. Gr.8 is good at resisting wear and tear but stainless would outlast it the chain links. Truly insane performance.
Only guy on the u tube vid that performs accurate interesting vids besides this great guy is project farm. Both supply non bias very detailed vids. Thanks.
The algorithm sent me here, holy shit you know a lot about bolts, and holy shit is there a lot to know about bolts. And I'm absolutely watching the whole video.
Great bolt test, I used to have explain the difference in bolt grades a lot while working for HD, despite working in plumbing. I have a mechanical background (a lot of shade tree hotrodding) as well as other areas. Would love to see you test the different grades of nuts soon.
For those who may be unaware, there are torque yeild charts that give the yeild (failure) torque based on grade and thread pitch. They allow for a small margin of error and are very useful when sizing replacement hardware.
Not all metric SHC are 12.9. They do come in 10.9 as well, though rare and hard to get here in the states. Where I work, our German presses use a lot of 10.9 SHC bolts because 12.9 is too hard and do not have the "give" that a 10.9 does so they tend to just break if they're substituted. We also use L9 bolts on our tumbler drive units per the manufacturer. They're the only thing that can handle the stress of being constantly vibrated and hold the drive and weights in place. Anything else will snap in a matter of hours. If I remember right though, L9 bolts are mostly used in aviation.
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Save for a few exceptions, yellow bolts these days are not Cadmium plated because that's a heavy metal, they are yellow zinc as mentioned. Think we should have tested them more like how they do in labs? That info is already easily found, we're using these how people in our jobs might. It's also *IMPORTANT* to understand we're yielding these bolts, because its fun and we wanted to see them fail and where. But the climb up the curve is where they should be used, not near at or past the crest because that's when they are stretched and toast. These values drop when using an equally low grade nut, but we're usually threading into parts like a steering knuckle. Not an opposing nut, so just eliminating variables. We keep bolt trays like Class 8.8: amzn.to/37PtUnD and Grade 8: amzn.to/3Cu6sq3 pretty close by when working on stuff around here. And they make flange head sets for automotive: amzn.to/3vqw5XO Has saved my bacon a number of times!
What else do you want to see tested?
i've always used grade 8 when replacing bolts. this video was very informative thank you for your hard work.
There's so many different grades and styles of fasteners out there you could probably do a whole other video. Allthread, Structural bolts, chrome molly, and lots of special application stuff like custom age or cryo treated. In heavy industry we come across a lot of weird specialized stuff that you probably couldn't find unless lifted off a job. Thanks guys it's always interesting.
Some classic test to fails would be wheel nuts and drain plugs. How much gorilla can wheel nuts take?
John Cadogan has a few videos on high tensile bolts, how they behave and the science/engineering behind them. Might be worth a watch and seeing how that information plays into your tests here
Great video. I work at a heading shop that makes automotive fasteners and have always been curious about this kind of info. If you are looking for more to test let me know
This channel is nothing but straight information with zero fluff or filler. Don't ever change.
What about that 30 second intro though?
@@nachoisme It's 9 seconds :P
@@TorqueTestChannel I summary at the end would have been helpful, I don't care to watch every step, just give me the data
@@andy2108if you buy something from their store, or buy access to it off etsy (iirc it's ~$15), you get access to every single spreadsheet they have made, forever
The only change I'd like is a spreadsheet with all past results like Project Farm has
Fantastic video. Very interesting.
I have a few comments from the perspective on an engineer.
1:50 - 18/8 is a stainless steel alloy, not a grade of bolt. It also called 304, or A2. It comes in its own three different strength classes - A2-50, A2-70 and A2-80. On metric fasteners this info is often stamped on the head. This steel can't be heat treated, as it doesn't have any carbon content (other than as impurities). The different strength classes are achieved through cold working the steel in this case.
8:36 - Grade 8 / 10.9 is always made from medium carbon (~0.4% C) alloy steel, quenched and tempered, never plain carbon steel. This is a requirement of the SAE/ASTM/ISO/DIN fastener standards. Plain medium carbon steel can't achieve these strength levels. Chromoly 4140 steel and 8640, 8740 are alloys often used for this grade for smaller diameters. For large diameters, 4340 is common.
11:10 - It is worth noting that metric 12.9 and ASTM A574 are standardized classes, but the so called equivalent "grade 9", as well as the bowmalloy are not (they are a product of some manufacturer that does not have to meet any legal criteria behind the manufacturer's promises). Therefore the last two will not be found in any product that needs to meet certifications.
17:45 - Regarding your question about the recommended torque specs, these torque figures are not really related to the maximum that a bolt can live with. Instead, they are calculated to generate a bolt tension/clamping force/preload that is equal to 75% of the bolt's proof strength. This guarantees reusability of the bolt after disassembly. The reason for it is that torque is a pretty poor proxy for preload - even among seemingly identical bolts torqued to the same spec, there is a +-30% variance in the generated preload. To make sure that a bolt does not yield, it has to stay below its proof strength. Hence if we calculate torque for 75% proof, and the natural bolt variance can mean that for some fasteners this will actually be 30% higher, we then get 0.75x1.3 = 98% proof strength, so even outliers won't deform and the bolts can all be reused.
In a permanent assembly, where fastener reusability is not a factor, the guideline is to use a torque calculated for 90% proof strength. Most bolts will not deform under this preload, but some will and will have to be replaced if it's ever disassembled.
If the engineer wants to use even more of the bolt's strength, he has to rely on more accurate methods than a torque figure, such as a specified degrees of turn from an initial snug position (you may recognize that from engine head bolts), a preload indicating washer, a yield sensing robotic wrench, or specified bolt elongation.
Regarding the failure point from torquing the bolt, it's not really something that can be usefully specified, both due to the aforementioned huge variability in torque, but mostly because the torque-preload relationship ceases to be linear once the bolt begins to yield.
Finally, in this specific video (not your usual impact tests), a better methodology would be to provide the dyno results as the gauge's direct reading of clamping force, instead of calibrating for torque, because
A. bolts are not chosen by the engineer to meet a torque figure, they are chosen to create some clamping force and the torque is calculated to generate this force. This torque is very different if the bolt is dry, oiled, greased, cadmium plated or used with anti seize, but the clamping force is the same.
B. You have to calibrate the dyno for every single bolt you test even if they're all the same size, due to the torque variability especially with unlubricated bolts.
C. Once a bolt starts to yield the multiplier constant in your digital gauge no longer converts the measured force to torque correctly, as torque no longer varies linearly with more tension.
Once again, this was a very interesting video to watch. If you ever do it again with a measurement of the force it would be very interesting to compare the ultimate force you get with the grade specifications. Should be essentially the same as a tensile test, and the forces should match or slightly exceed the specs.
Wow... you really seem to know about bolts 😲
I was disappointed to see they missed A325. we always use turn of nut method.
Excellent tutorial on what is really going on. Clamping force as per 'Faying Surface'
Thanks so much for the clarity.
It was hard to listen and watch some of this because some of the info was so wrong. Still worth watching, as it hard to find good comparison testing of bolts
I'm thinking we're on some of the same committees. Your points are spot-on and it is generous of you to take the time to clarify some important points for everyone here.
I would add to your comments on "18-8 Stainless" that the term '18-8' is not a specification but merely jargon. If one wishes to know what they are buying in a stainless steel fastener, then one needs to refer to a standard, and at times within that standard, a specific alloy or alloy group. ASTM F593 Type 304 for example. "18-8" merely refers to any steel with roughly 18% chrome and 8% nickel content. Since there is no standard for '18-8' one will end up getting whatever is cheapest presently. This is often 302HQ, XM7, or 303SE. Again without referring to a standard one could get any of these or something completely diffferent.
"Stainless Steel" is a confusing term in itself. The material origininated in Germany, back when alloys were trademarked if not patented. Early users of stainless steels included designers of skyscrapers -- who used it on the facades of the Chrysler Building (1930) and the Empire State Building (1931).
People are often dissappointed in stainless steel when it . . . . well . . . stains. This can certainly happen with Type 302, 303, 304 --- especially if passivation is not performed. Carbides on the surface left by tools used to form the parts can readily discolor the fasteners when exposed to moisture. Type 316 is the go-to for (consumer) marine applications. Navy fastener engineers (and subsea in particular) are the global experts in stainless steel and non ferrous alloys used to make fasteners for military ships.
Take-away: Choose your stainless steel alloy. Reference a standard. Don't simply accept '18-8' as meaning anything.
I’d like to to see the same test with ARP head studs. And compare to other head bolts or studs
ARP uses a variety of different materials, but below is a selection that you might find for head studs. (1 ksi is just 1000 psi)
ARP:
8740: 180 - 210ksi
ARP2000: 220ksi
Custom Age 625+: 260-280ksi
Factory LS metric 10.9 head bolt: 151ksi
This isn't completely apples to apples, as you'll get a little bit of extra clamping force out of the factory bolt by using the torque-to-yield procedure.
@@fastindy interesting info
Yesssssssssssssss please like Toyotas (TTY) bolts
I'd like to see that too.
@@fastindy What people don't realize is that you don't get anything additional from the stud if you don't tighten them further to the point where they're providing additional clamp load then the factory headbolt. The modulus of steel is the same, the only way this works as a performance increase is with more preload.
Interesting video. I’m a metallurgist and used to operate an accredited fastner testing laboratory. Nuts and bolts are a complicated subject. The way they are installed plays a huge role in how a threaded connection performs.
Spoken like a bolt manufacturer, always blaming the user for poor installation or misapplication. Just kidding, I'm an old QA manager reminiscing about the little daily wars.
Agreed Ted. I've seen grade 8 bolts snapped from hand tightening because a misaligned assembly caused bending of the bolt. Tension, torsion and bending combined can overwhelm a sturdy fastener.
Would be cool to see A325 (structural grade) on this scale
which one of these bolt could withstand the internal chamber pressure of a 7.62X39 cartridge?
@@toma5153you've seen a grade 8 bolt snap from hand tightening? 🤔🤨 If that's true then I seriously doubt that's a user error...
One could add, that the markings in the metric system actually make a lot of sense and tell you about the physical properties of the bolt. 10.9 for example: the first number (10) multiplied by 100 gives you the tensile strength of the bolt (1000 N/mm²). Multiply that by the second number (.9) and you get the yield strength of it (900 N/mm²). Simple as that.
everything in metric makes sense obviously !
It would be awesome if it was that simple. That would make 8.8 bolts have the same tensile and yield strength which could get pretty scary in practice. Actually the second number is a factor that is 10x the ratio between the nominal yield stress and the nominal tensile stress. Also the conversion from newton/square millimeters (N/mm²) to MPa is times 1. They are scaled the same, so no need for unit conversion unless you need SI base units instead of derived units.
@@adaycj 8.8 = 800N/mm² tensile (8x100) and 640N/mm² yield strength (8x8x10)
America is fucked all around even it’s measuring system.
Metric always makes a lot more sense than crappy inch luckily no one use outside of the US. In the US and CA, it is a nightmare because on the same truck, car etc... you find a mix of metric, UNC (the worst) and UNF (some easily confused with metric). A waste of money too !
I don't know if i'll ever use a bolt in my life, but my autism or adhd wouldn't let me stop watching this awesome and informative video.
I've used tons of stainless bolts for bolting together RF transmission lines that have bronze flanges with o-rings that have to bolt together to make an air tight seal but the also not corrode or react in the open air environment for 20 plus years. Biggest issue with stainless is galling, but they are quite durable and you don't have to worry about a rusted nut not coming off years later. The bolts we use come with a wax coating so they actually have a bit of a grey hue to them instead of being super shiny as the wax helps prevent galling as you tighten them.
the wax also prevents it from welding itself together.
I'm a boat builder and agree with you 100% . I've had the most trouble with trying to remove stainless nylocks, I think small nylon fragments wedge into the threads and increase the forces on the threads causing them to cold weld.
Sounds like EIA flanges. I've installed many of those (from 7/8" to 6-1/8"), on FM broadcast antennas and transmitters, both on the ground and in the air. There's nothing like being high up on a radio tower, discovering that the last guy over-tightened and galled the stainless bolts on some rigid transmission line sections, then struggling to shear them in half with the tools you have on hand. Then one of the bolts lets go suddenly, and you drop your wrench or ratchet... not that I'm bitter or anything.
@@Joel_E yeah the flanges I deal with are for TV broadcast in the six to 9 inch versions. Mostly made by Dielectric. 1500 to 1900 feet off the ground doesn't give a lot of forgiveness for dropped tools!
I build and service large fuel tanks for oil companies. Whenever replacing a seal on these tanks is pretty much guaranteed that I'm going to be replacing thousands of stainless ⁹/16 bolts due to galling..
Never apologize for a longer video. The more information out there, the better.
💯
I used to work as a maintenance engineer in two local chemical plants, we used some large steel “bogies”, which weighed several tonnes each. The shelves were held into the bogies using ¼ unc bolts at one of the plants and M6 cap head bolts at the other plant. The cap head bolts (12.9) used to shear off for fun, yet the regular ¼ unc bolts never did.
As for stainless bolts- they are a real pain in the backside, especially when they gall up and cannot be cut off with the gas axe!
If you use a 300 series SS bolt and nut, you’re in trouble. If you use a 300 series bolt and a 400 series nut(or vise versa), you’ll be ok. Another option is a SS bolt and a carbon steel nut. Dissimilar metals is the trick.
Great video. I am an engineer and have known what the outcomes should have been for a long time, but I rarely get to see heads up testing like this. Always neat to see the real world line up with the specifications that I use day to day. When they don't line up, trouble happens. :(
I broke a 10.9 OEM Ford bolt while trying to hit 129ft pounds. Shocked the hell out of me, and caused an 8hr recovery mission to remove the stud. Bought a generic bolt that has L8 on the head from Lowe's to hold me over. Deathly afraid of it breaking, so I watched this video then immediately ordered a grade 8 from Lowe's. Thank you for the help!
I used to work for Bowman. They are the company who originally created the Bowmalloy fasteners. They were bought by the Barnes Group and then MSC.
They kept the name due to industry recognition.
For a time, these were made in China and almost cost Bowmally their reputation.
I believe they have been brought back to domestic production now.
Yeah Briggs and Stratton brought back production to the states a few years back, I definitely notice the difference.
Thanks for the info.
And the 'illuminati' symbol is the Associated Spring logo because Barnes owns Associated Spring and the bolts were sold to distributors (like MSC) through their Associated Spring Raymond brand.
Good company. Knew your bolting guys very well. You guys used to source Bowmalloy at Lake Erie Screw Company (then in Cleveland) when the Wasmer family ran it. That was a classy operation -- on par with the best in Germany or Japan.
Which is a function of China having a tendency to say an alloy is someting it's not. China has great engineers. If they created alloys with the same demanding specs we do, they could of course produce bolts (or any metal item) with the exact same high quality the U.S. or Germany does. Throwing a bunch of scrap metal into a furnace and calling the resulting alloy "Grade 8" (or whatever) is the problem. They could produce quality if they wanted to.
Metric stainless fasteners are marked A2 or A4 for the material type (with A4 being higher corrosion resistant in salt water and chlorinated environments) and a number (50,70,80) that indicates its strength class, with 80 being equivalent to 8.8
As for the relationship between clamping force, torque, load, and so forth, there's whole engineering books about it, so the information exists, it might just not be explained in simple form anywhere easy to find. Odd. :) It would explain the amount of bolt abuse you see people do.
In short, the bolt fastening torque is mostly set to optimize clamping force. Clamping force makes sure that shear loads are absorbed by friction between the clamped faces, and that cyclical loading doesn't fatigue the bolt or joint.
A loose bolt would shear off or fatigue, or rattle around and damage the hole, where a properly tightened one would not.
An over tightened one could snap from being over tightened alone, or could damage whatever its clamping.
As for clamping force, what you mention is one part of it. To expand, the torque determined for a bolt is derived from the clamping force needed to maintain a sufficiently ridged connection. This is determined by the connection use, like clamping a pressure vessel, sealing a gasket, or affixing two solid objects together. Generally, you would choose the bolt grade based off of what your clamping force needs to be from the design criteria, not a tightening torque to prevent bolt damage. A loose bolt would also wallow the bolt holes or damage the clamped material, it most likely would not shear unless shearing impacts were applied, although a loose bolt will fatigue faster generally
For sure yeah, I think I probably could have worded my post a little clearer. Those design calculations also often show why multiple smaller bolts are better than one single big one, the clamping force is distributed much more evenly.
I think the times I've seen bolts shear clean off were indeed shock loaded in shear, which would have been find if they were tightened to spec.
Also, seeing people use loose bolts as hinge pins and shear loading the threads just really rustles my jimmies. At least use a shank bolt (-properly). Never mind actual proper ways to make bolted hinges.
Correct, very important to choose the right grade of corrosion resistant bolts (A2 or A4) with regards of the environment where they are used. A2 is good enough in fresh water, but will be destroyed in salt water over time. A4 is more expensive and contains additional Molybdenium in the alloy, hence more suited for salt water (or chlorinated) environment.
Tightening torque is based on 66%-75% of the tensile loaded yield strength, and depending on who is doing the calculating for that factor of safety. It has to do with avoiding fatigue, which is based on yield. Adding an axial load onto the bolt adds some tension and reduces some of the clamping load until the clamped pieces separate. For most bolts, this ratio is 0.33 * load applied added to the bolt, or less. I believe steel is usually .2-.25. This ratio of force applied is part of what makes proper torque avoid fatigue. If the total load of the bolt varies by 5% and doesn't yield instead of varying by 50% or more, that bolt will stand up better to cyclical loading.
As much as I like your videos, this particular test doesn't mean much. Torque is heavily influenced by the lubricant you use. Molykote P-37 generally has the most consistent results across materials. Unlubricated threads vary widely between material and coatings, not grade 5 to 8 but steel to stainless or Monel or K-Monel.
And a comment on grade 8 and harder alloy steels (>34 HRC or >150 ksi UTS). You should avoid any kind of zinc plating because it actually increases susceptibility to hydrogen embrittlement, which is a science term that means a bolt can break at 30% the rated load from environmental conditions. There is some debate where the exact cutoff is, but the toughest alloy bolts can easily lose a lot of their strength from a coating, sometimes before it is ever installed if it was done wrong (See San Francisco Bay Bridge failure where hot dipped galvanized bolts broke throughout)
For anyone interested, Fastenal has some great explanations of all of this: www.fastenal.com/en/69/bolted-joint-design
TL;DR. Bolt tension and reliability has a lot of factors and unlubricated torque runs til failure look nice but unfortunately don't really tell you much from a scientific point of view without concentrating on where they yield and controlling other factors by using a high quality lubricant, like Molykote P-37 or similar.
You're completely incorrect about the zinc plating. This is what I do for a living I make and test fasteners by the billions with a B. Zinc chromate plating is an extremely common surface finish. Every single lot is baked out for several hours after the plating process to drive any hydrogen out of the steel. Although in recent testing it's shown that anything under 34ish HRC is not susceptible to hydrogen embrittlement it's still done because it's written into the ISO and individual OE standards.
In addition to that Fastenal doesn't make a single fastener on their own, everything that they produce or sell comes from an established fastener supplier. They are not in any way shape or form a technical expert, they are just middleman distributors.
@@otm646 I just took an intro to matscie class and it's changed my entire world view.
The work you all do is sick
They don’t produce any? I thought they had multiple manufacturing facilities in the US? Also, don’t they own Holo-Krome and Cardinal?
@@otm646 According to ISO TR 20491 the cutoff is RC39. Also ASTM F1941 requires 12 hours of baking, not just a couple. And Fastenal does actually own several fastener manufacturers.
@@wcr2179 From what I can see(Mech-E) Fastenal is just a distributor. Though they "own" some manufacturing companies, whatever that means 🤷
There are tougher bolts out there.
NAS8906 go to 220kpsi and NAS8907 go to 260kpsi. They're used in aerospace framing and are single point turned rather than rolled on a screw machine, and have a tighter class of fit than normal threads. You have to go to a dedicated screw house for those, and are the last stop before custom designed solutions, like special alloys and ground threads.
Most applications care more about performance at temperature and corrosion rather than just straight performance though, which is why A286 and inconel screws are also a thing.
I've been to a dedicated screw house before, but I guess I must have overlooked the bolt aisle.
@@mediocreman2 Must've been there looking for a nut?
@@mediocreman2 The bolt aisle is the hallway you run down towards the back door when the cops raid the place.
You might know a thing or thee. Haha drives me nuts when people ask for the strongest bolts possible (a325 gr55/105 or some shit) because they saw marking on a bolt head in a building. Like mofo, your gar away from the "strongest". And what strong you want.
NAS also also have tighter tolerances than their AN cousins
Perhaps a test of thread lube? Grab a bunch of those grade 8 bolts and slather them in various thread treatments... ARP ultra, motor oil, a few greases, anti-sieze, threadlock, etc. You could test torque consistency and overall torque before failure.
@trashcanmucous5153
Hmm, that is a good question. My first thought would be some anti-seize, as that its purpose.
But plastic doesn't weld to metal, it can only melt or deform like clay.
Is it feasible to add a material in between the parts like a film, wax paper, or bushing?
I'm tremendously grateful for this very informative video. It's most definitely not too long.
This channel is easily as good as TH-cam's best channel, Project farm.
No messing around, just facts.
Grade 1 and 2 are fine for most wood fastening applications, since the wood will fail before the bolt. The carriage bolts you are testing are a good example - if building a wood carriage, just use grade 1.
Many people assume a higher grade bolt it better in all applications. This is incorrect. Some bolts are intended to fail to prevent more severe damage. Some bolts are better at shock loads than others. For instance, bolts on suspensions are intentionally not high grade, because higher hardness is usually more brittle, and the impacts in the suspension mean that high grade fasteners may snap during use. Lower grades will stretch, and that stretching and loosening of the fastener can be accommodated in the design, since the major loads can be designed in shear and not in tension.
The torque applied to the fasteners is also sometimes more critical than people assume, and too tight can often be a very big compromise to the fastener. Preloading the tension or creating additional stretch reduces the capability of the fastener in tension and in shear. Each application presents a window of proper torque for the fastener, including whether clamping force is required or just sufficient force to prevent the fastener from backing off. These windows also depend a lot on the fastener grade and thread configuration.
Agree , was in the cold heading trade for 15 yrs. There's science behind all of it.
Very good explanation
The amount a bolt will stretch and return to its original size without fatigue is known as the elastic range, the harder the material the shorter the range.
Very worth the watch. Where else are you going to see this kind of demonstration?
14:04 FYI, that's just the Bowman Distribution company logo (now owned by Barnes) and doesn't necessarily mean it's their proprietary high strength alloy. I've got an entire bolt bin of old grade 5 bolts with the Bowman logo on the head. Great video as always!
Years back I had to replace 288 1" bolts that were holding a ski lift together because they were counterfeit. They had been in use for 35 years and none of them had ever failed and none of them broke on removal even with about 10 coats of paint on them and rust. A325 bolts and A563 nuts were all torqued to spec in a 3 step process 50-80 feet up the towers.
Better safe than sorry. Thank you for doing whats right to ensure others safety. Also, thanks to whomever noticed the wrong fasteners and demanded them replaced. Standards exist for a reason.
You could have saved many lives by replacing those bolts, who knows how strong the original ones were…
@@jason86768 , @NFR Computers It was the elevating device authority in my area that brought it to our attention. The reason the counterfeit bolts had been supplied was a weird story that had mob ties. 3 of the prior lift maintenance managers had ignored the warnings and when I took the job I inherited a stack of papers outlining safety infractions that were ignored for years. My signature on the daily logs was enough of an excuse for me to take action. Sadly since I left that job ,all things safety and common sense related have been ignored. While at the facility this year I brought up many safety problems with several board members and was told to mind my own business. They will eventually hurt or kill someone.
The bright side, at least, is that the myriad of coats of paint show that maintenance wasn't _completely_ ignored.
A325 is a standard bolt for structural steel with oversized head's and nuts
I make bolts in a literal bolt factory- and I had learned absolutley none of this through my work. So thank you. Fascinating.
Great video. No need to apologize for the length - it's as long as it needs to be to explain the results!
One thing I would like you to try.. apply some anti seize to the stainless before it's run. reason being stainless binds up when heavily impacted. the antiseize keeps it threading freely.
That would likely change the measurements a lot. That's the equivalent to lubricating the bolts beforehand
You never use lube on Torque tests. Possibly Locktite in some special circumstances in Process equipment
When I took the plow mount off my truck I found out the shop that installed it used stainless bolts to fasten the two pieces together. Was shocked to find 304 stainless was able to withstand the punishment of finding hidden obstacles albeit they were large 5/8 bolts. I would suspect smaller diameter bolts wouldn't fare so well. Nice to see an actual test comparing them to steel counterparts. McMaster-Carr carries an extreme strength stainless that is supposedly comparable to grade 9, would like to see that compared to 304/316 and 18-8.
Very informative and well put together video. I went back to college around 20 years ago to finish my engineering degree. I always found testing and comparing similar items to be quite fascinating. Nope, I'm 54 this year and still haven't finished my engineering degree. In the meantime I've acquired close to a dozen different degrees/ licenses. Quite honestly, it won't make an ounce of difference if I finish my engineering or not. In Canada, once you have reached 65 years old, you can return to college at zero cost. Maybe I will finish my engineering then. I just hate not finishing something that I started.
Thanks for the testing. I have always used minimum grade 5 bolts and mostly use grade 8. I avoid grade 2 or below as much as possible. Glad to see your testing results showed the difference. Appreciate your videos.
Always use antiseize on stainless bolts for stainless pipe. I learned that the hard way when I had to cut almost all the bolts out on the job site.
One thing I noticed, when I would tighten stainless steel bolts with stainless nuts, very tight, is the threads tend to "gaul" and seize up. Great test THANKS
@@wadesaxton6079 can you please give a reference that confirms that torque figures are wet ? I heard the opposite, at least for automotive
@@francoisloriot2674 automotive is dry.
Never have used ss we didn't never seize first
Doing a boat motor mount that has to hold a 170 lb 25 hp motor. It is cantilevered 28" out off the boat due to needing to clear a swim platform. Glad that stainless steel bolt was slightly better then the grade 5. I am using 1/2 stainless bolts just like this for holding that motor mount to the transom.
Now all I gotta do is engineer that transom reinforcement properly on the back side and I should be good to go. Thanks so much for doing this video. I feel much better now about those stainless bolts.
The motor mount is 6061 12x13, 3/4 thick plate with 6061 2x6x.250 tube between the transom plate and the motor plate, it is tig welded with 300 amps by a guy who does many hundreds of feet of tig welds per year. Why that aluminum plate and tube? It is just what I could scrounge up.
Yes, stainless steel plate is very expensive, so it's a money saver using aluminum. 6061 - T6 is hardened aluminum, but as long as your not near salt water it will last. Retired welder.
This is cool and especially interested to see how the 304 stainless bolt does. Many think it's perfect due to corrosion resistance compared to normal steel and strong stainless but I believe they are probably below grade 5 strength due to brittle nature of stainless. I will see if I'm right as I watch!
Ok watched it and I gotta say I'm surprised by the stainless result! I agree that I've been confused by spec sheets and avoided stainless fasteners in more important areas due to fears of overall strength - I usually figured less than grade 5. But this test showed it much closer. Id imagine the application still will matter such as static fastening vs shear forces on the bolt attachment. Still neat data so thank you!
I agree. Did better than expected but also it's too wishy washy of a distinction to assume grade 5 equivalent. Shear strength shows a wide range of acceptability.
Stainless also has the problem of galling, which steel doesn't.
Yeah, rebuilt my motorcycle with pretty much only stainless bolts since the original ones were so rusty. Never making that mistake again haha
@@TorqueTestChannel Just an FYI, not all 18/8 alloys are 304, and not all 304 alloys are 18/8. Type 304 is 18-20% chromium, and 8-12% nickle, but also maximum 2% manganese, 1% silicon, 0.045% phosphorus, 0.03% sulfur, and 0.08% carbon. Generally 18-8 bolts are cheaper/worst quality than a 304, but can be stronger due to carbon content, especially in forged fasteners. Also 18-8/304 are only freshwater compatible, you need 316 for true saltwater resistance. Though even 316 can rapidly corrode in anaerobic situations due to crevice corrosion. The molybdenum in 316 makes the fasteners tougher than 304, but softer. So higher yield, lower tensile. Also using stainless isn't recommend for any torqued application is the threads galling. So its easy to torque the fastener correctly, but have little to no clamping force.
thanks buddy. I put up a gantry crane and one end is supported by carriage bolts. Didn't realize their lack of effectiveness as a fastener until your enlightening video. did wonder about their strength rating though. Didn't know about the grade 1 rating. Crazy, but I thought grade 2 was the bottom of the barrel. and I come from an industrial background! We never used anything less than grade 2, the flat heads, or stainless, but mostly grade 5 or higher rating. The other end of the gantry is supported by grade 8 bolts though. Now I only have a 1 and 1/2 ton chain fall on the beam, but you can be sure I will change out the carriage bolts for grade 8. As an aside the gantry is 18' long with 12 carriage bolts scattered from center to one end and another 12 grade 8 bolts scattered from center to the other end. I believe in over doing it in the name of safety. Don't want anyone getting hurt.
The vortex pattern of every sheered bolt tells a story of heavy lateral torque as well as some tensile loads, and remember these books are graded for tensile loads, not lateral torque load, but very cool video on bolt strength!!
The best way to test these bolts is to load the nut to a common ft/lb then hang weight from the bolt 🔩 to achieve a purely tensile load.
There is no way you could be too Loong in making a informative video. I learn as much as I need to know from your videos as I do from Project Farm and belts and Boxes.
Thank you for helping me understand Bolt grades.
really interesting seeing these torque values with impact guns. most high torque applications are done with hydraulic wrenches or hydraulic bolt tensioners which are not comparable in any way to impact guns. good work on this channel. consistently impressed with the stuff i'd like to know but have no intention of going through the effort to find out myself.
Love to see bolt specs finally tested! This is particularly valuable info for a home gamer without a torque testing setup to be able to test their impacts at home with some degree of accuracy, my method has always been to set it to max power, stick the bolt/nut in a vise and see how high a grade/size it’s able to break or strip the threads out of
Two major flaws here that are likely to mislead interpretation. The first issue is "18-8" is not a specific alloy, it just designates a generic stainless with a minimum 18% chrome and 8% nickle content, but there are many alloys that contain that amount of Cr and Ni.(Stainlesses also have other engineering considerations such as pitting corrosion and corrosion fatigue which do not effect non-stainless in certain corrosion environments.)
The second and bigger issue is not using a standard EP thread lube. By standard I mostly mean using the same grease for all tests but preferably a lube meant for the task eg ARP sells one. EP for screw threads is usually a solid additive like moly or graphite as opposed to the surface active additives more common in EP gear lube. This is especially important for austentic stainless which are very prone to galling (microwelding and plastic surface deformation) especially when used with a matching stainless nut. (As is normal because dissimilar metals in contact will corrode much faster.) The standardized lube takes out the surface finish variable(major) and overall reduces the torque component of stress relative to axial stress. Surface finish and lube choices can change the ideal torque for a fastener by 70%
Non-EP lubes like motor-oil are only consistent at low torques on low grade bolts, they can't maintain a significant separation film between the metals under high pressures at these low speeds. (High speeds suitable to form sufficient dynamic film strength would be like 2000rpm+ at this small diameter and high pressure.)
Didnt have to scroll gar to find the metallurgy guy in here haha
I really love how you broke down everything with charts to better understand.
You earned a subscriber.
Great video. It's only telling part of the story(arguably the most interesting part). Different grades have different applications based on whether they bend or stretch, or just snap.
The Bowmalloy is a very unique bolt. They are actually manufactured by Barnes Inc. And commonly used by Barnes Aerospace. The head marking is actually a spring from the Barnes logo. Bowmalloy is designed to retain the hardness and tensile strength of a grade 8 bolt, but bend without snapping. They were designed to be used in the aerospace and space programs where vibrations were a concern. You can take a Bowmallow bolt, bend it in half without it snapping.
I love these straight forward videos without the fluff and thirsty requests to “like and subscribe” and unwanted advertising. Just on that alone, you got a like, and a new subscriber.
I run stainless bolts all the time at work, biggest issue I've run into with them is the gall super easily
Copper anti-seize is a must with stainless fasteners!
Antisieze is a must with stainless fasteners if you want them to come apart again.
@@JonMarshAnderson can't use it on food processing equipment
@@bigj231 I try to use food grade antiseize when I can, but it's not always practical when its in a heavily washed down area
@@Respawntheskullpupper Dang, I’m in the fertilizer biz so nothing is sanitary haha but everything is stainless
I make threaded fasteners every day. There is so much more that goes into it than you could explain in a single video.
This was a great idea for a video from you guys. Thanks for all that you guys do!
Also, you mention being car dudes, and I'm curious what you guys drive.
whatever the Mrs. isnt, i see by your avatar.. you know...
I was always told when I was growing up that the purpose of bolt grades wasn't for tension but for their shear resistance. We would use grade 5 bolts as a sort of fuse for our grain augers to keep a potential clog or other fault issue from destroying the internal auger. I would hear tales of my grandad shearing a G5 bolt and swapping in a G8 to get the last of the load finished, but at the expense of completely mangling the auger with the extra torque applied from the shear resistance of the G8. We had a specific box of "cheese" bolts for our smallest augers as even G5 would be too strong to fail under a fault.
I spent 6 years working in Aerospace, I'm curious how aerospace grade bolts would compare. Might be worth a video, I know the prices on these bolts were ridiculously expensive, would be funny for your community to lose their minds over the prices of each
I was wondering where the NAS bolts would test. They’re rated 180,000 psi tensile and 95,000 psi shear.
You can snag them surplus quite reasonably. Found some for a few bucks a piece to repair an industrial grandulator. The blade mount bolts were very similar in spec to the aerospace bolts except they had a torx type cap instead of the hex cap. Was for a Cumberland B60 grandulator machine. 🤓
@@christopherleubner6633 At least you know it will meet/exceed the original bolt lol
We use the Bowmalloy bolts at work for adjusting clamping force on vibrating material handling equipment(which is a great way to make small adjustments to the vibration), you really need to use torque wrenches with them. Unlike grade 8, it's very hard to tell by feel if they are about to yield. And they are very hard to drill out and remove from the equipment once they break off.
Would be interesting to see the same test performed by hand instead using an impact.
Also why no lube? Lube shouldn't impact the clamping force or material properties of the bolt. You would just need less torque to reach the failure point.
Lubrication dramatically changes the clamping force at a given torque. In a joint with a lot of friction, most of the torque applied goes into overcoming that friction. Add lubrication and a lot more of the torque actually goes into advancing the fastener and generating clamp.
@@danieljackheck That's is exactly what I am saying. The peaking clamping force won't change because that is a function of the yield strength of the bolt, but you will need a lot less torque to get there.
Great video! 35 year industrial maintenance man and engineer here, and I have been down the rabbit hole of bolt ratings for certain high stress applications many a time.
18-8 isn't a bolt rating - it's another type of Stainless steel, like 316 or 301 or 304.
So when you see it on a bolt head, it's designating that it's Stainless and which type of Stainless.
Different Stainless steels have different corrosion and magnetic properties, and in many applications those are what matter the most over torque, toughness, and hardness. Many Stainless bolts are very close in the torque, toughness, and hardness ratings, so the differing properties of the different kinds of Stainless tend to come into play.
304 is an 18-8 aka 18% chromium 8% nickel
18 series is what most ss cooking pans are made of.
Awesome testing!!
Now, engineers everywhere... "Yeah I know the bolt isn't rated for it but TTC told me it can do 2x, should be fine."
No, TTC SHOWED ME.
@@mookfaru835 Touché, sir!
Lol we showed you how to ruin them. With a grade 9 opposing nut as well. Use the charts to determine where it's still within plastic deformation and would go back to being a happy bolt (the climb up) and where it's no longer a happy bolt (peak and cresting over).
@@TorqueTestChannel Potato Potato
Saving this video for reference purposes. Thank you for this.
This is great! You could do many more tests with various manufacturers.
IF .. and its a huge IF.. one could definitively determine primary source in chy nuh
Just a comment on your conversion from pressure to torque: this is dependent on the friction coefficient in the thread and between washer and nut.
So for different surface treatments of the bolt there will be a different conversion factors.
Also, your recommended torque should ensure that you don't exceed 90% of the bolt's yield strength when tightening. When your pressure curve flattens, you already exceeded the yield strength of the bolt
One of my first experiences with 1 time use bolts was on a flywheel to crank bolt on a Nissan 240sx. When re torquing the bolt it snapped pretty quick. Very brittle. Nissan had them in stock for $6 a piece like 20 years ago. My buddy says BMW uses a fair amount of 1 time use aluminum bolts. Save a little weight.
One time use bolts= head bolts for Diesel engines...those are "stretch bolts" They only stretch once.VW had them with a Torx socket head. Can reuse them -just not to tighten down heads. $6 each & there were 10 of them.
I work in steel fabrication. We fabricate the steel for wherehouses and schools. A307 bolts are bottom of the barrel but are used in nearly building for non-inportant pieces. A325N and A325TC bolts are the ones that hold the stairs, beams and tubes together. Pretty much everything structural
In my experience as a mechanic/ hobby fabricator stainless bolts snap or stretch far earlier than anything else. I won't use then unless it's for a low torque submerged application.
I use them for outdoor decking and stairs. Haven’t had one break and it doesn’t look ugly after 2 years
I think it depends on he manufactura and application they were intended for. I have experience with true stainless exhaust bolts and nuts an they love ceramic paste because the threads wear out quickly in compariso but they do not snap or stretch. They are between 8.8 than 5.8 but closer to the first.
I was told not to use stainless hardware on my beadlocks. a tone of people said they were weak and would snap so I put one in a hole in a metal table and bent it with a hammer. they are strong enough for what I want to use them for. glad to see you confirm that hard to find info or test on them
I wish you would have included 316 Stainless as it offers better corrosion protection than 304 Stainless Steel.
I'm not sure most people understand why studs are preferred over bolts when it comes to things like the heads on an engine.
Interestingly the answer is right there in the name of your channel, torque. Studs yield more consistent and accurate results over plain old bolts.
I don't know why it took me so long to come across your channel but, I love it. The information you provide is clear and useful. After watching the first video I immediately subscribed.
Keep up the great work my friends.
Hey thanks! Yes, consistent bolt tension is the name of the game. Input torque is sort of a crude way to get to bolt tension, but a fixed stud with nut is the best way to get there, especially with a known K value (lube)
My old boss wanted to put in used regular non grade bolts in a man lifts castor wheels. They would put wedges in the lift leg sensors to trick the machine into thinking the legs were down and in place and all the weight would be on the wheels, that way they didn't have to mess with the legs and lock out system when they did light changes in the gyms. They just wanted to roll a guy 30 feet up from light to light and save time!! I told him to go to hell and I wouldn't be going in it ever again. I was 3 weeks in that job, but I couldn't let him do that and kill me or someone else.. after that I was on the gotta go list and only made it over a year before getting fired over "budget" cuts..
Loved to watch this video, however I have a small point.
9:40 The yield point of a bolt is not when it starts losing tension (graph line goes down again) but it is the transition between the steep uphill and the flat lining.
In technical terms the yield point is described as the amount of stress a material can take where is plastically elongates 0.2% over its original length measured after unloading.
What you were reffering to is (close to) the ultimate tensile strength. UTS is a measure of stress which is force over area. The cross sectional area changes as a bolt gets stretched so the UTS of the material actually gets reached after the curve goes down again in terms of pure beans.
In material stress tests it's critical to measure the area of the snapped off samples to determine the actual stress in the broken region.
Rant over, keep up the great videos!
This is the way.
I’d like to see how a titanium bolt would compare since they are commonly use in raceing applications
Titanium is actually very brittle. You wack the typical racing pedal with a 3lb mallet, it'll shear clean off.
I'm also not sure how much titanium is used in these applications, by the way. You'd have to test specific products. It's quite common for commercial products to be electro plated or finished with a metal, and then sold with that branding. It's not a 100% solid product or even an alloy in many cases. A good example of this is cookware. Stainless steel cookware is the name of a finishing, isn't made from any stainless steel. Cast iron isn't solid cast iron. Copper isn't copper. Etc.
It’s used for its strength to weight ratio which is much higher than steel, not for its ultimate tensile strength
No expert but 316L SS is the typical go to alloy for Marine , and other chemical environment applications. 304 SS is a good rain 🌧️ resistant alloy. Great video and thank you for all channel content!
There is an EXCELLENT lecture series on fastener physics that NASA uploaded to youtube from the 90s or something. That's where I learned that lock washers don't do squat! It's phenomenal!
th-cam.com/video/D6zaVhQkwnY/w-d-xo.html&ab_channel=NASASTIProgram
Specifically, _split lock washers_ are useless.
ntrs.nasa.gov/api/citations/19900009424/downloads/19900009424.pdf
Some background from a BSc student Mechanical Engineering: It is not weird that the hardened bolts fail/shear in the tests with the Thor impact. The hardening makes the metal brittle, whereas the cheap bolts will just stretch. It is like comparing a brittle cookie to a flexible rubber band. So for their application (high strength fixing) they are great, because the rated tightening torque is well below failure point and these bolts will withstand a lot more in their lives. And the "weak" bolts are usefull in applications where only low strength is required (in cost considerarion), or even in flex/movement compliant design (wood construction for example) .
Very interesting to see this theory applied! I like your videos!
Many failures occur from overly hard studs/bolts being used in areas of extreme temperature change. Think engine exhaust manifold bolts.
Great test of coarse thread bolts. The same test with fine thread bolts and comparing to the coarse thread bolts would be informative. Fine threads are much stronger. In many cases, the bolt is using the sheer strength of the shaft more than the clamping strength of the threads.
I understand SAE nominal same size "course" thread bolts have a smaller minimum cross section thickness than "fine" thread ones giving a stronger tensile strength. (In the same grade)
the course thread valleys are deeper.
@@davidpowell3347 Yes, the sheer strength of the shaft is stronger, because it has a greater cross section.
Can we all just stop to appreciate the fact the availability and common use of these bolts at their price is amazing? 100 years ago this would be unheard-of.
The problem with using stainless bolts is that if you over tighten them, the threads of the bolt and nut can gall together and are nearly impossible to remove without cutting it off
Never apologize for length of videos. I appreciate the data and the format is about as efficient as it can be while still being entertaining.
That was...awesome! Thank you! Any chance you can do something like deck/wood screws? Im dying to know if some of the stuff is worth the money. Thanks!
Project Farm did some comparison testing of them along with Stumpy Nubs.
@@kjdude8765 I've seen the Project Farm video on them, I'll have to check out Stumpy's. I realize now I wasn't super clear in my comment, I said deck/wood screws, but I was thinking the larger stuff like the standard lag screws/bolts, timberlocks, GRX Lag replacements, etc. For instance GRX claims their thinner lag screw replacements are stronger than the much thicker standard lag screws/bolts. I'd be curious if their claims are true, and if they are, how much stronger are they? Just an idea, maybe this is more suited for Project Farm as a follow up video to the first one on wood screws.
@@justtime6736 I generally do. My asks are generally around comparisons of more expensive items, the ones I really want detailed information on to make proper buying decisions. It'd be nice if he would mix more of that stuff in. At least do 1 or 2 for seasonal stuff, for each season. Eh...but I'll take what I can get, bit drivers it is...lol!
I've worked with a lot od stainless steel fasteners in food processing equipment. Mainly for corrosion resistance, not so much for strength. Lots of 'Ny-lock' nuts there, not actually for any real 'locking' ability, but for their resistance to falling off if they get loose, and damaging equipment.
Then I've also spent a lot of time working on machine-tools, and heavy equipment. Lots of 'Allen' head fasteners, they are usually in recessed holes where you don't want a lot of material removed, or more often clearance issues, so you have the head of the Allen bolts in holes recessed to just a few thousands of an inch clearance.
I'd love to see a shear comparison if you have the setup to accommodate. Particularly interesting would be under load or torqued to the recommended value. If the shank diameter is the same across grades the shear limit may not be (speculation) greatly effected by a loaded or unloaded bolt.
Ya that would be interesting.
definitely want to see single and double shear, as in a shear pin.
Thanks. I chose Grade 8 bolts this week to bolt down my new vise - 8" jaws - don't want it to move when I'm working with it.
Yay, we're not getting ripped off!
If anyone was scratching their heads at the introduction of the 304 bolt at 1:44, in which it was called "non-steel, non-ferrous": 304 _is_ steel, and it _is_ ferrous, being an alloy of 60-something% iron (the rest being a lot of chromium and nickel, plus 11 secret herbs and spices). However most of that iron is in the form of austenite, and austenitic steel is non-magnetic, which I suspect is what they meant to say.
304 is magnetic tho. Go into your kitchen with a magnet and check your "Stainless" knives. Bet you some, if not all are magnetic.
@@Mp57navy I didn't say 304 is non-magnetic, I said the austenitic steel in it is. Steel is never truly homogenous; different ferrous structures crystalize and come out of solution at different times/ temperatures during manufacture. The resulting alloy is never 100% of just one type of cubit-faced crystal. That's why I specified _most_ of the iron in 304 is austenite.
@@Mp57navy Your knives aren't T304, they're be a 400-series, and that's martensitic (and magnetic).
I'm glad you guys really got into the nuts and bolts of this one
Oh, another thing about stainless bolts. While there's a big temptation to use them on headers (and other exhaust parts) it's not a great idea. As they heat cycle, they loose a lot of their ductility and become brittle. Then they just snap. All it takes is the thermal expansion of the flange, and it can rip it in half.
I just need to correct you on one fact: Socket head cap screws are indeed available in classes lower than 12.9. I have some class 10.9 and some class 8.8.
All right, now try a collated self tapping bugle head modified truss serrated flange lag bolt… 🤣 Great video, we actually have a lot of people buy stainless steel bolts for Parks and Recreation/outdoor applications at the store I work at. I always tell the people that grab the stainless steel bolts that they will break very easy.. they never listen! 😂
lemme see. stainless.. ok great!.. what were u sayin?
Not a problem if they properly lubricate the thread to prevent galling.
Hot dip galvanized are fine for wood playsets and furniture. Almost any fastener is strong enough to crush wood fibers.
you show also values in "normal" measurement system - I love it
What torque wrench are you using? Monkey brain neurons are activating because of the cool colors
Matco digital. It hurts the wallet but very good
You left out nuclear grade fasteners-
Nuclear grade, the exact type as any other but priced 1000 times more.
Structural Engineer and ICC Structural Steel & Bolting Special Inspector who works at nuclear plants. A325s are A325s whether they're being used in a support structure holding up a steam generator at a nuclear generating station or in a pre-engineered metal building for a dollar store. The main difference is the paper trail creating traceability for every bit of that bolts life from raw material to install.
_I used A325s as an example, but the same goes for any grade bolt._
Do you mean monel, Inconel and hastelloy? They're favoured for corrosion resistance in very salty applications (think like 304 is for seawater, it doesn't necessarily mean is stronger). But, I agree, it would be cool to see on the charts.
If you do this test again, I would love to see a comparison include 17-4PH and A193 Grade B6 bolts. In the line of work I do we have to use both of these a lot.
If you wanted to go all out, ASTM standard A540 has some wild hardware to check out.
Cheap carriage bolts are fine for connecting soft wood together because the head snd nut sink into the grain. I’d not use them anywhere else.
I'm 70+, never gave my wheel bolts/nuts a second thought. Guess people like us had a lucky star looking after us/me. Thanks for the knowledge!!!
On metric rating the first digit is actually the value in Newton (N) times 100 per mm². So 8.x is 800N per mm². So you can calculate the strength on each bolt yourself without looking up a table if you calculate the cross section.
The second digit in the metric rating is only indirectly related to strength, it indicates the point where it starts to stretch WITHOUT going back to its original form. So x.8 = 80% of 800 = 640N per mm² it will start to stretch.
Also I learned that if you use a "softer" nut you can achieve a higher torque before breaking since the treads can distribute the load over several treads on the nut and not all is concentrated at one point. In fact: Using a harder nut than the bolt is, might be very counter productive.
I did not know about the US rating system, it was interesting to see. I like your tests! Please keep doing them 🙂 👍
Great Video, this actually helps me understand now why "factory torque" is important to follow when putting on wheels etc, (Tighter does not always mean better lol) otherwise you could stretch out the threads or snap the bolt etc. Thanks again!
An almost perfect experiment, thank you for sharing.
One little critics, you should have considered the length of thread for each bolt. As you know weakness comes from root of the bolt thread and when you apply force on threaded part length of thread and elongation make the difference.
Respect from Türkiye
I enjoy watching your tests. I believe they show fair comparisons that give insight into how selections should be made.
In regards to the stainless bolts consideration has to be given to the service they are going to be used. My background is with oil tankers. We specified stainless bolts be used on deck and in tanks for corrosion resistance. In general stainless is a good choice. However, we found we had fatigue failures on bolts that were used in areas where there the bolts were exposed to high cyclical loading such as the mounting of hydraulic valve cylinders. Proper alloy selection along with tensile strength needs to be taken into consideration.
Another issue with stainless steels is their corrosion resistance. There are significant differences between alloys. Having a stainless bolt does not mean it won't corrode.
Thank you all for the helpful information! Now I know what "grade" bolts to use when I rebuild my LR4 motor. I was confused as to which was better, but this clears up my confusion. I am so grateful for your time and hard work!
Great and useful video, thanks so much! Stainless steel deck screws are far weaker than any steel screws, so I assumed the bolt would be weaker. I had to use a drill with a clutch, my little impact driver kept twisting them off. So that 304 / 18-8 bolt was s surprise.
I like to use a lot of Grade 8 bolts and "Grade 8" Nylock Nuts and especially "Grade 8" (aka hardened), washers b/c the washers don't deform under load/tightening.
I find the Yellow zinc coating present on most "Grade 8" stuff to be FAR superior for weather/rust resistance then standard zinc.... I buy them in bulk b/c the cost difference does not seem to be that great over grade 5 (and is sometimes cheaper from one of my suppliers for some reason)
They are also often available cheaper than grade 5 zinc in "plain" finish which makes them very easy to weld prep and paint b/c you don't have to strip the zinc off before hand.
Grade 5 Plain finish and Yellow Zinc are also available and I often purchase those as a "lower" strength alternative... But unless they are substantially different prices Grade 8 is my go to for anything not requiring stainless or Hot Dipped (I always buy grade 5 hot dipped b/c the ungraded bolts especially carriage bolts seem to be made of "Cheese grade" steel)
The quality of the fasteners/threads & finish etc is WAY better then buying the garbage sold in most hardware stores and big box stores and when purchased in bulk are WAY cheaper then that crap.
Exactly even if you need 50 bolts pay the Xtra 50$ cadmium bolts are okay for furniture but not for something that can fail.
I use to work in a lumberyard and we would use chains in the winter and they were secured with a carabiner. Gr.8 is good at resisting wear and tear but stainless would outlast it the chain links. Truly insane performance.
Only guy on the u tube vid that performs accurate interesting vids besides this great guy is project farm. Both supply non bias very detailed vids. Thanks.
The algorithm sent me here, holy shit you know a lot about bolts, and holy shit is there a lot to know about bolts.
And I'm absolutely watching the whole video.
Great bolt test, I used to have explain the difference in bolt grades a lot while working for HD, despite working in plumbing. I have a mechanical background (a lot of shade tree hotrodding) as well as other areas. Would love to see you test the different grades of nuts soon.
For those who may be unaware, there are torque yeild charts that give the yeild (failure) torque based on grade and thread pitch. They allow for a small margin of error and are very useful when sizing replacement hardware.
Great and useful information! I recently had a discussion about this very topic with one of my friends while we were working on my car.
We're torquing M16 12.9 to 340nn ±20 for decades , but I've stepped in to lower it down to ~280.. This video just proof me right!
Not all metric SHC are 12.9. They do come in 10.9 as well, though rare and hard to get here in the states. Where I work, our German presses use a lot of 10.9 SHC bolts because 12.9 is too hard and do not have the "give" that a 10.9 does so they tend to just break if they're substituted. We also use L9 bolts on our tumbler drive units per the manufacturer. They're the only thing that can handle the stress of being constantly vibrated and hold the drive and weights in place. Anything else will snap in a matter of hours. If I remember right though, L9 bolts are mostly used in aviation.