i would love to order from this, but its too expensive. you are from finland, but you offer an american product. if i were to order the cheapest product, which is 33 USD, use the promocode, then 23 USD remains. but i live in the Netherlands. after shipping and taxes, total price, with promocode, is 37,53 USD!! that is way too much! why dont you offer a european product for europeans? its way too expensive now, and i wont buy :(
@@sollitdude1 We have more viewers in the US than in europe so it makes more sense to promote products and services for them. Some times its but annoying to not be able to order the stuff to Finland. For example macig spoon serials would be definetly on my menu if they wpuöd just ship here 😂
As cool as it would be, it would not work very well for this specific test. Since the metal is somewhat reflective, the thermal camera will just see the metal as a mirror. I've tried to measure temps of aluminum heatsinks and just saw reflections off the metal
Thread stripping is always expected on the bolt before the nut. As suggested it is because the shear plane is at a larger diameter. This means there is more area for the shear force to act over. The formula for thread stripping is roughly: Thread profile width (half pitch) * Diameter at shear plane of thread (this is bigger for nut than for bolt) * Pi * Number of threads of engagement.
@@TheAlexfooooo Yes but I've rarely seen that (at least across industrial equipment). The only reason is if you had a threaded stud that's welded or pressed in in an unserviceable area.
FWIW, that approximation only hold up till the nut length is around half the diameter of the bolt. Once it gets longer than that, the decreasing axial load on the bolt from the loaded end of the nut to the other and the resulting elastic deformation gets large enough you an start to strip the threads at the loaded end well before you fully load the threads at the other. A few more threads and you might not even load the far end at all before pealing threads off. (That said, if you need to hold an impulse, more threads do continue to increase the amount of *energy* needed to fully pull the bolt thought the nut out of the hole.) IIRC standard nuts a just long enough to get something like 90% of the max. (It's been a while, so it might be 80% or 95%, but it's in that ballpark.)
@@benjaminshropshire2900 thanks for your comment. interesting. i'd like to know a bit more about the impulse half of it, if you know where i could look into it more. thanks.
You could take full size nuts and bore them out to the desired number of threads. That should remove the material thickness of the nut as a variable and prevent the cupping.
@@d46512 in my opinion no: I think that if you remove the threads from the bold when you press it in the threads don't have anything "backing them" Of course in the nut happens the same thing but as we crearly saw in the first test the nut bends before the threads fail, so, if you have only 1 thread but the nut can't bent in my opinion it should be stronger
Mechanical Engineer here, general rule for designing: half the thread diameter for a nut. If you do the proper calculations, it mostly depends on the material of the nut. Funny enough, the nut is usually stronger than the bolt in order to see threads shearing off before part faillure occurs.
As a toolmaker lifting heavy injection moulding tools we go by a rule of 1.5x diameter minimum for lifting eyebolts so m30 needs 45mm of thread to lift its rated capacity
@@lukearmsby5507 I believe you are correct that's always what I've heard. But do not definitively know. But I will say it's definitely gonna depend on whether it's coarse thread or find thread as well.
I think you made a typo, the material of the bolt is most important as you say that is the part that fails. And not because the thread but because shear forces. No engineer is going to design a construction where the nuts gets pulled from the bolt that is terrible idea. What is tested here is something that should never happen. if you have something pulling on a bolt you are going to use a system with a pin. Only pressure on a nut should be by tension set to cause friction between the parts you want to pull together.
Shadetree mechanic here. Common sense dictates that thread diameter and nut material are irrelevant, and that one should simply turn both until a pop is heard, then back off 1/4 turn.
A graph of the amount of force over the number of threads would have been a good way to visualize the results. Once trace for the cut down nuts and one for the bolts. Otherwise, stellar video. These are really interesting.
Assuming a grade 8 bolt using UNC threads, the 1st thread usually takes 34% of the load. The 2nd about 23%, 3rd-16%, 4th-11%, 5th 9% and 6th takes about 7%. Depends largely on material, though.
Another Mechanical Engineer here! From the Strength of Materials class in the first year we were taught that the first three threads (in tension) take 98+% of the load. Since you are testing in compression the results are different. BTW ASMET and BSMET, retired after 40+ years in Forensic Failure Analysis ...
They take 98% of the load until elasticity is reached for those threads. 100% load is gained when total thread contact equals diameter of bolt. Basic mechanics.
@@aresorum Most materials are stronger in compression than tension. 10,000 psi tensile strength steel will take more than that in compression. Concrete for example is the same way...
Mechanical Engineer here. If you are really interested look up the Handbook of Bolted Joints by Bickford. When designing joints you have to do much more than look at the shearing of the threads. The industry usually dictates how joints are designed. Steel Construction, Piping, Aerospace, etc all have different standards.
Would be curious to learn what "absorbing force" really means in terms of physics. Maybe the nut threading is deformed such that the contact area with the bolt threading is bigger, is that what you mean?
@@Aviator_Shades initially yes, but I was also thinking that the deformation of the thin nuts compresses the material at the top of the nut tightly around the bolt threads. This might add a mechanical clamping element as well as closing all the tolerances between the nut and bolt threads?
To be fair, I think 9:36 the peak from the threads was 19K, while 26K was the peak from the press slamming into your test equipment due to the sudden release of the threads.
@@Finnspin_unicycles Do you mean like the 'rule of thumb' which says the thickness of the nut should be at least the diameter of the bolt? en.wikipedia.org/wiki/Machinery%27s_Handbook
@@brucepeebles4939 That rule probably arrived from similar testing, but standard height metric nuts are designed to not fail before the corresponding bolt yields, and have less then 1x nominal thread diameter of thickness. Anyway, my main point was that I guarantee someone who is much more appropriate to cite than a TH-cam channel has done similar testing, so you are (unfortunately) unlikely to see any HPC video as a source in scientific papers.
One of your best videos ever. This is a serious technical issue that you would think has been settled since threaded fasteners we're invented but reading the comments I keep seeing "rule of thumb". You're just sciencing the shit out of this! Somebody had to do it and I'm glad it was you. I hope other TH-camrs follow in your footsteps on this topic. What I did not expect was the sudden failures of the multi thread nuts. I expected the single thread nut to do that, not to bend. Finding out you were wrong is the best part of doing science!
Here's my guess before watching the video: 7 (based on existing tests I've heard about). It seems that 4 threads was surprisingly strong already. However, it seems you measured *compression* when real world bolt usage will see stretching forces only. Logically compression forces make the bolt thicker so it should make the connection stronger. Of course, building a test setup that can those huge stretch bolts is much harder.
This is a topic I've actually wondered about in the past deciding if my jeep wheel studs were long enough for my wheel nuts to get maximum engagement. What I found in research was that the nut should have as much thread engagement as the bolt shaft is wide, minimum. In both your nuts and bolts here, the surface was machined into, decreasing the case hardening of the nut or bolt. The only way I can think of the avoid that is to only screw an uncut nut onto an unmachined bolt as many threads as you want to test. Good video, thanks.
The cupping deformation is interesting, since when it deforms like I think that the interior diameter should get wider at the bottom and the nut might "let go" of the lower thread. The bolts you made with only a few threads should be testing exactly that, since it's the same number of threads but without the nut easily deforming, but the results of that test were definitely strange. I'm sure at some point a manufacturer somewhere did all sorts of tests like this to characterize the standardized threads.
here in the USA I was taught the 3-thread rule for machine threads. For a strong, reliable hold you should have at least 3 threads completely screwed together. More is usually a bit better, but I was taught to not use anything less than 3 threads. This was a good video to see.
This was very interesting I’ve been an A&P mechanic for 47 years and our NAS manual on average requires two threads showing at a minimum after torquing a structural bolt. I’ve never seen an experiment like this, actually seeing when the nut failed. In most applications you’re looking at shear and tensile strength of the bolt and your tech data dictates the nut. I believe that the nut usually catches four threads and two showing after torque requirements. That would be six threads over all and I’ve never seen a structural bolt fail under normal operating conditions.
@@rkan2 I’m talking structural bolts in an aircraft application with thousands of pounds of pressure on each bolt in close tolerance holes. I’m not talking about bolting your muffler on. I’m an Airframe & Power-plant Mechanic. I’m talking about extreme loads.
Hi, Great video as always. You should (as you mentioned) test with a "pull" configuration. by testing pull strength, you would be able to check at which point adding threads is pointless because threads are strong enough to break the bolt itself.Here, you really tested the material strength and the differences you saw, were probably caused by different alloys from which bolts and nuts are made. Cant wait for pull test wideo.
I'm an engineer and I've actually studied this. You are testing the nuts with the bolts in compression. Normally nuts are used to put bolts in tension, and in that application the distribution of load in the threads will change, usually the first 3 or so threads are taking most of the load. There is a real old book by D. G. Sopwith called "The Distribution of Load in Screw Threads" that goes into this quite a bit. This is counting on a full size nut so the nut itself doesn't deform the way your thin nuts are deforming.
A structural engineer I worked for used to say it’s 1 to 1. So what ever the bolt diameters is, that’s the amount of thread required. Simple to remember and easy to implement.
I might have overlooked, but I would love to see these graphed in a diagram for even better visual understanding between thread numbers / pressure - that would make the comparison even more striking!
The answer, according to basically every bolt manufacturer on the planet is 7. 7 threads, regardless of fastener diameter or thread profile or thread pitch will essentially guarantee a failure would be the entire fastener and not the threads. This isn't a mystery they did all these exact tests thousands of times in the 1940s
@@peacefrog0521 There are 2 types of pleasure in this world that we shall never experience: To be a tool in the hands of Lauri and to be the face of Lauri in Anni's hands.
In actuality I think this is testing 'threads' or area of mating surface of threads, or shear strength of metal at area of base of threads. Probably some algebraic equation for it. Lol! Love your vids!
When you had the one thread with the full bolt, the press made contact with the left side of the bolt before it made contact with the right side of the bolt resulting in a lot more pressure on the thread on one side which made it real easy to go through.
I actually did a whole project on this exact concept for Mechanical Engineering school. We developed our own equation to calculate the force based on thread engagement. It was pretty fun and interesting.
This is the only channel where the sponsor ads are sometimes BETTER than the regular content! The sponsors should pay extra for that. I learned as a young engineer that the nut is pretty much always stronger than the bolt.
And why is that, Timmy? Because interior threads are stronger than exterior threads! If you reverse the way the threads are cut on the nut vs. the bolt, then the opposite will be true.
If the nut and bolt are the same grade of steel, it makes sense that a single nut thread will be stronger than a single bolt thread because of the greater diameter of the nut compared to that of the bolt. There's simply more steel there. Fascinating stuff!
I think the thinner nuts might deform and pinch the shaft of the bolt, adding some friction. If you squish the threads of the nut and the bolt into each other they may also mesh a bit better and not shear as easily.
I'd consider taking a whole nut and bolt but removing some threads from the nut so you lower the number of threads as my theory is that the nut leans on lower threads as it deforms, so when you stripped the bolt you removed that which skewed your results
As a machinist of 45 years, it was widely accepted that a minimum of three full threads of engagement was necessary to achieve acceptable fastener specs.
Really interesting results. I would have liked to see a graph of force as compared to number of threads and more numbers of thread tested. I would have expected a continuous linear progression with increase in the number of threads, since each thread takes some amount of force to shear, and I would expect that to stack.
that was a pretty loose fitting nut - different grade bolts, different thread pitches, and different classes of fit, of the same diameter bolt, will have a dramatic impact in the results
Hello HPC. Greetings and hoping all your windows are properly sealed. Nearly winter, and Finland does not do winter halfway. Meant to be a cold, snowy one this time. So, the rule of thumb in mech engineering is the threads engaged should be at least 1.5 x the bolt diameter. Cylinder head bolts show this works. On aluminum engines you have to use low torque to avoid warping around cylinder studs, while coping with huge heat and pressure variations. High load stress situations need a minimum of 1.5 x bolt diameter of bolt protruding beyond the nut, the theory being it's easier for the bolt to tolerate the load by spreading the load away from the nut. Given enough space. No space, increase bolt diameter. We used this simple solution for decades on heavy railroad applications. Few failures, even at -50 c or lower with vibration present. Looseness or shock loads, at lows temps all bets are off, it's going to break pretty quick. Keepeace. ( traditional Finnish toast)
That’s the one I’ve always gone by, as a mechanic. You have to assume that the thickness of a full nut has been calculated by someone for optimum strength!
Great video! I love watching this press break stuff. You should set up another test and pull the bolts out of the nut. Once you get enough threads it should be stronger than the bolt itself. Keep up the awesome press work
This is a very good point, testing in compression you totally lack the threshold cross over where the threads become stronger than the bolt. Which is the key importance of this test in reality.
Makes sense to me. Some energy goes into deforming the nut itself when it flexes, with the complete nut and partial threads on the bolt, all of the energy goes into the threads themselves. Hence less total pressing force required
I believe that because the nut was cupping the top thread or threads were being pushed tighter to the bolt making it harder for the bolt to pass. I think if the die you’re using was just big enough for the bolt to pass and the pressure was only being applied very close to the inside of the nut your results would mirror each other much closer.
I find this incredibly intriguing to watch even if I'm not entirely sure that the results are actually useful for from the perspective of understanding the strength of a fastener (I could be convinced either way). All the bolt "rating tests" I've seen have been under tension, and in every scenario, the bolt itself snaps and the threads do not fail. Seeing the threads themselves fail seems to be a scenario an engineer would not be accounting for, since that is not the designed mode of failure. Super fun videos nonetheless, I'd love to see more!
The general rule is: you have to have the same amount of threads in the nut, as the width of the Bolt. In other words, if you have a 3/8 by 2-in Bolt, you have to have a nut with 3/8" of threads to be equally as strong. Your nut would have to be 3/8 of an inch.
I'd assuma the threads on the bolt are probably supported in part by the threads above too. Which would also explain why bolts with partial threading are as thick as the threads in the area where there are no threads.
The rule of thumb for sound design is thread engagement needs to be equal to diameter of thread as a minimum for reliable performance, erring for at least one or two threads more as a safety factor.
The number of threads takes into account the shear and surface pressure conditions. The threaded connection is not meant to be one-time, to prove something, it is necessary to check at what load can still be unscrewed. What class was the bolt in, and what was the nut? What was the size and thread pitch?
It makes sense why it was weaker in the bolt than in the nut; within the nut, the threads are attached to a larger surface, it's anchored in a way, with a rough triangular shape to the anchor. For the metal to shear and snap and break the threads, it has to heat up, which expands it, right? The amount of mass surrounding the nut thread prevents there expansion. On the bolt, it has nothing to restrict the expansion of the metal.
When we saw the bolts threads sheared off as rings, the first thought that came to mind was that milling the threads off the upper portion of the bolt introduced a second variable, as the bolt threads had no reinforcement.
I'd be interested to see what happens with interrupted threads with the same size nut. Like how is it any different with two 45˚ opposed sections of thread removed from the bolt shaft vs three equally spaced 30˚ sections vs a single 90˚ section removed, and how much weaker is the bolt with two 90˚ opposed sections of thread removed vs three equally spaced 60˚ sections and finally 180˚ threaded and 180˚ smooth. I have a gut feeling that evenly spaced interruptions to the thread will be stronger than a single large one of the same size but I don't know why.
I would love to see this test in tention. I would also like to see the test with more threads, I've been told that only the first four or so threads do work and the rest don't add much. I'm not sure if this is referring to threats that brittle fracture, or threads that yield like this.
The herzberg contours means the compression force is not optimally linear. Think about the variety of postional applications. Olams radial rule is in effect with this alloy also 👍
Just what I wanted to know first thing this morning! My day will now be much improved, regardless if I need to decide if a nut is strong enough for the job it's going to be used for or not haha.
How about fine threads vs coarse threads? How about a rig to stretch the bolts with the press rather than compress them - can you hold the head in place with fingers then press a nut threaded onto it with non-meshing fingers, stretching the bolt? Or would the nut fail first?
It makes sense it should basically scale linearly with number of threads except in the case of 1 and 2 threads you lose some extra because of the cupping distorts the mating of the threads with the bolt so it is easier to push through.
If you look back at single thread bolt with all threads, it starts bending around same time as machined bolt. But the machined bolt doesnt have threads beside the bending thread to catch it so it maxes out lower.
Great video! But why not have a tension load in the bolt instead of compression? That would answer question how man threads you need to reach same strength as the bolt. Generally you are comparing shear vs tension. In some cases you want the bolt to fail before the nut. You adjust the nut width accordingly. 👍
This is actually a really good example of bolt strength. They all saw thread shear failure on the nut and we know that each thread can take about 25,000 lbs force.
Thread strength is ultimately dictated by shear force as long as the base material is strong enough for deformation to be negligible. You get less incremental strength from excess extra threads since bolt stretch puts most of the load on the leading threads. There is no point in having more threads what the bolt will yield at.
Fun tech called flow drilling has to answer this question with its use! In general, the first two threads take up 60% or so of the load, and it’s pretty negligible by thread 5 I believe.
The force on the threads doesn't care if it's a push or a pull, the threads would have to pull on the nut hard enough for the shaft to start necking before it would make any difference, my bet is push vs. pull is exactly the same.
For a moment I thought you had fingernail polish but I quickly realized that it must be Anni. Great video and very nice of Anni to apply the cream to your face. Thanks
Always wanted to see the difference between a fine thread nut and bolt vs a corse thread like fine med and corse witch is the strongest that might be cool to see in the press. Love your channel alway fun to see your experiments so cool.
Click here tiege.com/hydraulicpress to get 30% off your first Tiege Hanley box plus a FREE gift! Let me know what gift you got in the comments below!
Do their skin treatments help reverse the effects of Anni's Napalm Lotions? 😂
You have lovely fingernails, Laurie. 🤩
i would love to order from this, but its too expensive. you are from finland, but you offer an american product. if i were to order the cheapest product, which is 33 USD, use the promocode, then 23 USD remains. but i live in the Netherlands. after shipping and taxes, total price, with promocode, is 37,53 USD!! that is way too much! why dont you offer a european product for europeans? its way too expensive now, and i wont buy :(
@@sollitdude1 We have more viewers in the US than in europe so it makes more sense to promote products and services for them. Some times its but annoying to not be able to order the stuff to Finland. For example macig spoon serials would be definetly on my menu if they wpuöd just ship here 😂
Sounds just like my wife 🤣🤣
I'd love to watch this with a thermal camera and see how much the temperature changes as the metal is forced
High-speed thermal camera would be cool
For a second there I thought you where going to say when he was getting his face moisturizer applied! 😋
for certain crushes i would love to see this as well as with a schlieren setup
Please do this
As cool as it would be, it would not work very well for this specific test. Since the metal is somewhat reflective, the thermal camera will just see the metal as a mirror. I've tried to measure temps of aluminum heatsinks and just saw reflections off the metal
Thread stripping is always expected on the bolt before the nut. As suggested it is because the shear plane is at a larger diameter. This means there is more area for the shear force to act over.
The formula for thread stripping is roughly:
Thread profile width (half pitch)
* Diameter at shear plane of thread (this is bigger for nut than for bolt)
* Pi
* Number of threads of engagement.
Glad real engineers commenting and not just armchair warriors like me.
I thought it was common practice to spec a lower grade nut. Grade 5 nut with a grade 8 bolt for example. Wouldnt The opposite be true in my case?
@@TheAlexfooooo Yes but I've rarely seen that (at least across industrial equipment).
The only reason is if you had a threaded stud that's welded or pressed in in an unserviceable area.
FWIW, that approximation only hold up till the nut length is around half the diameter of the bolt. Once it gets longer than that, the decreasing axial load on the bolt from the loaded end of the nut to the other and the resulting elastic deformation gets large enough you an start to strip the threads at the loaded end well before you fully load the threads at the other. A few more threads and you might not even load the far end at all before pealing threads off. (That said, if you need to hold an impulse, more threads do continue to increase the amount of *energy* needed to fully pull the bolt thought the nut out of the hole.)
IIRC standard nuts a just long enough to get something like 90% of the max. (It's been a while, so it might be 80% or 95%, but it's in that ballpark.)
@@benjaminshropshire2900 thanks for your comment. interesting. i'd like to know a bit more about the impulse half of it, if you know where i could look into it more. thanks.
You could take full size nuts and bore them out to the desired number of threads. That should remove the material thickness of the nut as a variable and prevent the cupping.
Exactly what I thought, before the video even started playing!
That would also allow the testing of hardened nuts
Isn't that equivalent to what he did on the lathe?
He could have also used a much closer fitting bottom die so everything was in shear rather than bend.
@@d46512 in my opinion no: I think that if you remove the threads from the bold when you press it in the threads don't have anything "backing them"
Of course in the nut happens the same thing but as we crearly saw in the first test the nut bends before the threads fail, so, if you have only 1 thread but the nut can't bent in my opinion it should be stronger
Years later and this channel is still great. You guys bring so much happiness into my life.
Yeah I always come and binge on a load of their videos every month or so. I don't know why crushing things is so satisfying 😂
Just over seven years. Happy belated, HPC!
He doesn't just crush things, he satisfies some technical curiosities, like here with nuts and threads
Mechanical Engineer here, general rule for designing: half the thread diameter for a nut. If you do the proper calculations, it mostly depends on the material of the nut. Funny enough, the nut is usually stronger than the bolt in order to see threads shearing off before part faillure occurs.
As a toolmaker lifting heavy injection moulding tools we go by a rule of 1.5x diameter minimum for lifting eyebolts so m30 needs 45mm of thread to lift its rated capacity
@@lukearmsby5507 I believe you are correct that's always what I've heard. But do not definitively know. But I will say it's definitely gonna depend on whether it's coarse thread or find thread as well.
I think you made a typo, the material of the bolt is most important as you say that is the part that fails. And not because the thread but because shear forces. No engineer is going to design a construction where the nuts gets pulled from the bolt that is terrible idea. What is tested here is something that should never happen. if you have something pulling on a bolt you are going to use a system with a pin. Only pressure on a nut should be by tension set to cause friction between the parts you want to pull together.
I didn't know what the reason was but it was something I had noticed
Shadetree mechanic here. Common sense dictates that thread diameter and nut material are irrelevant, and that one should simply turn both until a pop is heard, then back off 1/4 turn.
A graph of the amount of force over the number of threads would have been a good way to visualize the results. Once trace for the cut down nuts and one for the bolts.
Otherwise, stellar video. These are really interesting.
Assuming a grade 8 bolt using UNC threads, the 1st thread usually takes 34% of the load. The 2nd about 23%, 3rd-16%, 4th-11%, 5th 9% and 6th takes about 7%. Depends largely on material, though.
I agree. When doing tests like these I would love to see a graph so I could visualize the data.
Another Mechanical Engineer here! From the Strength of Materials class in the first year we were taught that the first three threads (in tension) take 98+% of the load. Since you are testing in compression the results are different. BTW ASMET and BSMET, retired after 40+ years in Forensic Failure Analysis ...
They take 98% of the load until elasticity is reached for those threads. 100% load is gained when total thread contact equals diameter of bolt. Basic mechanics.
Why does compression and tension results differ?
@@aresorum Most materials are stronger in compression than tension. 10,000 psi tensile strength steel will take more than that in compression. Concrete for example is the same way...
Mechanical Engineer here. If you are really interested look up the Handbook of Bolted Joints by Bickford. When designing joints you have to do much more than look at the shearing of the threads. The industry usually dictates how joints are designed. Steel Construction, Piping, Aerospace, etc all have different standards.
Does the Continental version have decimal points or commas? A lot could be explained....
@@xroqus wut?
You are exactly right. The bolt threads always fail before nut because of the smaller root diameter (or diameter near the solid metal)
The cupping of the thin nuts absorbs some of the force. With the modified bolts, the threads take all the force.
always make sure to cup the nuts
Would be curious to learn what "absorbing force" really means in terms of physics.
Maybe the nut threading is deformed such that the contact area with the bolt threading is bigger, is that what you mean?
Ah yes the cupping of his special nuts
@@landsgevaer I think he means the nuts absorb some of the force because they deform under pressure, similar to the shock absorbers on a car.
@@Aviator_Shades initially yes, but I was also thinking that the deformation of the thin nuts compresses the material at the top of the nut tightly around the bolt threads. This might add a mechanical clamping element as well as closing all the tolerances between the nut and bolt threads?
To be fair, I think 9:36 the peak from the threads was 19K, while 26K was the peak from the press slamming into your test equipment due to the sudden release of the threads.
10:00
Seeing your hand next to the bolts made me realise that the bolts are pretty huge. Nice video!
I love HPC videos that make me think "I wonder if this'll ever be sourced in a materials science paper"
I'd like to think so. Thunderf00t has been cited, so I wouldn't be surprised if HPC gets cited too.
Maybe, but I assume that a whole lot of testing like this has been done to arrive at the standards we have in the first place..
@@Finnspin_unicycles Do you mean like the 'rule of thumb' which says the thickness of the nut should be at least the diameter of the bolt? en.wikipedia.org/wiki/Machinery%27s_Handbook
@@brucepeebles4939 That rule probably arrived from similar testing, but standard height metric nuts are designed to not fail before the corresponding bolt yields, and have less then 1x nominal thread diameter of thickness. Anyway, my main point was that I guarantee someone who is much more appropriate to cite than a TH-cam channel has done similar testing, so you are (unfortunately) unlikely to see any HPC video as a source in scientific papers.
K.k.kķ0p
One of your best videos ever. This is a serious technical issue that you would think has been settled since threaded fasteners we're invented but reading the comments I keep seeing "rule of thumb". You're just sciencing the shit out of this! Somebody had to do it and I'm glad it was you. I hope other TH-camrs follow in your footsteps on this topic.
What I did not expect was the sudden failures of the multi thread nuts. I expected the single thread nut to do that, not to bend.
Finding out you were wrong is the best part of doing science!
Here's my guess before watching the video: 7 (based on existing tests I've heard about).
It seems that 4 threads was surprisingly strong already. However, it seems you measured *compression* when real world bolt usage will see stretching forces only. Logically compression forces make the bolt thicker so it should make the connection stronger.
Of course, building a test setup that can those huge stretch bolts is much harder.
You should crush powdered candy with rock maker to make a jawbreaker
Maybe they could use sugar water or honey as a sort of glue.
The elements will hold and be Intresting to see what happens. Hope they will try this
Pop rocks would be my next choice.
Great idea
*Yavbrreaker, as they pronounced it years ago
This is a topic I've actually wondered about in the past deciding if my jeep wheel studs were long enough for my wheel nuts to get maximum engagement. What I found in research was that the nut should have as much thread engagement as the bolt shaft is wide, minimum.
In both your nuts and bolts here, the surface was machined into, decreasing the case hardening of the nut or bolt. The only way I can think of the avoid that is to only screw an uncut nut onto an unmachined bolt as many threads as you want to test.
Good video, thanks.
The cupping deformation is interesting, since when it deforms like I think that the interior diameter should get wider at the bottom and the nut might "let go" of the lower thread. The bolts you made with only a few threads should be testing exactly that, since it's the same number of threads but without the nut easily deforming, but the results of that test were definitely strange. I'm sure at some point a manufacturer somewhere did all sorts of tests like this to characterize the standardized threads.
But wouldn't that also mean that the upper part of the nut would get tighter? Offset effects?
First 3 threads holds about %80 of the force that acts.
here in the USA I was taught the 3-thread rule for machine threads. For a strong, reliable hold you should have at least 3 threads completely screwed together. More is usually a bit better, but I was taught to not use anything less than 3 threads. This was a good video to see.
This was very interesting I’ve been an A&P mechanic for 47 years and our NAS manual on average requires two threads showing at a minimum after torquing a structural bolt. I’ve never seen an experiment like this, actually seeing when the nut failed. In most applications you’re looking at shear and tensile strength of the bolt and your tech data dictates the nut. I believe that the nut usually catches four threads and two showing after torque requirements. That would be six threads over all and I’ve never seen a structural bolt fail under normal operating conditions.
Most bolts in automotive applications will almost always outlast any other fixing methods!
@@rkan2 I’m talking structural bolts in an aircraft application with thousands of pounds of pressure on each bolt in close tolerance holes. I’m not talking about bolting your muffler on. I’m an Airframe & Power-plant Mechanic. I’m talking about extreme loads.
after all these years you manage to keep a simple idea interesting and engaging
Hi, Great video as always. You should (as you mentioned) test with a "pull" configuration. by testing pull strength, you would be able to check at which point adding threads is pointless because threads are strong enough to break the bolt itself.Here, you really tested the material strength and the differences you saw, were probably caused by different alloys from which bolts and nuts are made. Cant wait for pull test wideo.
I'm an engineer and I've actually studied this. You are testing the nuts with the bolts in compression. Normally nuts are used to put bolts in tension, and in that application the distribution of load in the threads will change, usually the first 3 or so threads are taking most of the load. There is a real old book by D. G. Sopwith called "The Distribution of Load in Screw Threads" that goes into this quite a bit. This is counting on a full size nut so the nut itself doesn't deform the way your thin nuts are deforming.
It is important to mention Bolt specifications, i.e. material, diameter and thread specifications; also add about Nut specifications.
Thanks
A structural engineer I worked for used to say it’s 1 to 1. So what ever the bolt diameters is, that’s the amount of thread required. Simple to remember and easy to implement.
Anni the hand model is perfect!
I might have overlooked, but I would love to see these graphed in a diagram for even better visual understanding between thread numbers / pressure - that would make the comparison even more striking!
We need to see this same test again but with whole bolt and 2 whole nuts
The answer, according to basically every bolt manufacturer on the planet is 7. 7 threads, regardless of fastener diameter or thread profile or thread pitch will essentially guarantee a failure would be the entire fastener and not the threads. This isn't a mystery they did all these exact tests thousands of times in the 1940s
4:46 could be an entire video. Look how sweet Anni is to moisturize Lauri's face. Next level ASMR!
I laughed out loud OMG. And she had just showed off the nails too by wiggling them at the camera... LOLOL!
I thought it would be a remake of U2’s “Numb” video 😂
@@peacefrog0521 There are 2 types of pleasure in this world that we shall never experience: To be a tool in the hands of Lauri and to be the face of Lauri in Anni's hands.
Miss Anni for sure.
That face was hilarious!
In actuality I think this is testing 'threads' or area of mating surface of threads, or shear strength of metal at area of base of threads. Probably some algebraic equation for it. Lol! Love your vids!
Im glad you are happy with promoting skincare products , more men especially in the industry need to take better care of themselves
When you had the one thread with the full bolt, the press made contact with the left side of the bolt before it made contact with the right side of the bolt resulting in a lot more pressure on the thread on one side which made it real easy to go through.
I actually did a whole project on this exact concept for Mechanical Engineering school. We developed our own equation to calculate the force based on thread engagement. It was pretty fun and interesting.
This is the only channel where the sponsor ads are sometimes BETTER than the regular content! The sponsors should pay extra for that.
I learned as a young engineer that the nut is pretty much always stronger than the bolt.
And why is that, Timmy?
Because interior threads are stronger than exterior threads!
If you reverse the way the threads are cut on the nut vs. the bolt, then the opposite will be true.
If the nut and bolt are the same grade of steel, it makes sense that a single nut thread will be stronger than a single bolt thread because of the greater diameter of the nut compared to that of the bolt. There's simply more steel there. Fascinating stuff!
Good to hear Anni's laugh in a video again.
I think the thinner nuts might deform and pinch the shaft of the bolt, adding some friction. If you squish the threads of the nut and the bolt into each other they may also mesh a bit better and not shear as easily.
I second this.
I'd consider taking a whole nut and bolt but removing some threads from the nut so you lower the number of threads as my theory is that the nut leans on lower threads as it deforms, so when you stripped the bolt you removed that which skewed your results
As a machinist of 45 years, it was widely accepted that a minimum of three full threads of engagement was necessary to achieve acceptable fastener specs.
Really interesting results. I would have liked to see a graph of force as compared to number of threads and more numbers of thread tested. I would have expected a continuous linear progression with increase in the number of threads, since each thread takes some amount of force to shear, and I would expect that to stack.
that was a pretty loose fitting nut - different grade bolts, different thread pitches, and different classes of fit, of the same diameter bolt, will have a dramatic impact in the results
Hello HPC. Greetings and hoping all your windows are properly sealed. Nearly winter, and Finland does not do winter halfway. Meant to be a cold, snowy one this time.
So, the rule of thumb in mech engineering is the threads engaged should be at least 1.5 x the bolt diameter. Cylinder head bolts show this works. On aluminum engines you have to use low torque to avoid warping around cylinder studs, while coping with huge heat and pressure variations. High load stress situations need a minimum of 1.5 x bolt diameter of bolt protruding beyond the nut, the theory being it's easier for the bolt to tolerate the load by spreading the load away from the nut. Given enough space. No space, increase bolt diameter. We used this simple solution for decades on heavy railroad applications. Few failures, even at -50 c or lower with vibration present. Looseness or shock loads, at lows temps all bets are off, it's going to break pretty quick. Keepeace. ( traditional Finnish toast)
This video is absolutely awesome: funny, informative, interesting and funny!
Well done, mate!
i'm a journeyman pipefitter and the rule we use is the thread engagement has to be the same as the stud diameter
good point about the diameter of the thread base in the nut vs the bolt. force is spread across a significantly larger area in the nut.
I believe a 'rule of thumb' for maximum strength is the number of threads (thickness of nut) should be at least the diameter of the bolt.
That’s the one I’ve always gone by, as a mechanic. You have to assume that the thickness of a full nut has been calculated by someone for optimum strength!
Great video! I love watching this press break stuff. You should set up another test and pull the bolts out of the nut. Once you get enough threads it should be stronger than the bolt itself. Keep up the awesome press work
wouldnt pulling the bolt have the same result as pushing it?
@@dhc2 when the bolt fails in the feild it will fail in tension or sheer. Its really strong in compression.
This is a very good point, testing in compression you totally lack the threshold cross over where the threads become stronger than the bolt. Which is the key importance of this test in reality.
It would also be interesting to see you test different thread counts on the same sized bolt.
Ive always settled for the diameter of the bolt, try and use nuts of similiar thickness as bolt diameter. Always proved very effective.
Makes sense to me. Some energy goes into deforming the nut itself when it flexes, with the complete nut and partial threads on the bolt, all of the energy goes into the threads themselves. Hence less total pressing force required
I believe that
because the nut was cupping the top thread or threads were being pushed tighter to the bolt making it harder for the bolt to pass.
I think if the die you’re using was just big enough for the bolt to pass and the pressure was only being applied very close to the inside of the nut your results would mirror each other much closer.
I find this incredibly intriguing to watch even if I'm not entirely sure that the results are actually useful for from the perspective of understanding the strength of a fastener (I could be convinced either way). All the bolt "rating tests" I've seen have been under tension, and in every scenario, the bolt itself snaps and the threads do not fail. Seeing the threads themselves fail seems to be a scenario an engineer would not be accounting for, since that is not the designed mode of failure. Super fun videos nonetheless, I'd love to see more!
The general rule is: you have to have the same amount of threads in the nut, as the width of the Bolt. In other words, if you have a 3/8 by 2-in Bolt, you have to have a nut with 3/8" of threads to be equally as strong. Your nut would have to be 3/8 of an inch.
I'd assuma the threads on the bolt are probably supported in part by the threads above too. Which would also explain why bolts with partial threading are as thick as the threads in the area where there are no threads.
The rule of thumb for sound design is thread engagement needs to be equal to diameter of thread as a minimum for reliable performance, erring for at least one or two threads more as a safety factor.
Oh yeah, a new hydraulic press channel video! LET‘S GO!
Finally some science experiments and not just messing about. Really great video!
Destructive testing is my favorite kind of testing.
The number of threads takes into account the shear and surface pressure conditions. The threaded connection is not meant to be one-time, to prove something, it is necessary to check at what load can still be unscrewed. What class was the bolt in, and what was the nut? What was the size and thread pitch?
It makes sense why it was weaker in the bolt than in the nut; within the nut, the threads are attached to a larger surface, it's anchored in a way, with a rough triangular shape to the anchor. For the metal to shear and snap and break the threads, it has to heat up, which expands it, right? The amount of mass surrounding the nut thread prevents there expansion. On the bolt, it has nothing to restrict the expansion of the metal.
Your english has gotten a lot better since i started watching you in 2017
When we saw the bolts threads sheared off as rings, the first thought that came to mind was that milling the threads off the upper portion of the bolt introduced a second variable, as the bolt threads had no reinforcement.
This is, by far, my favorite hydraulic press video
I'd be interested to see what happens with interrupted threads with the same size nut. Like how is it any different with two 45˚ opposed sections of thread removed from the bolt shaft vs three equally spaced 30˚ sections vs a single 90˚ section removed, and how much weaker is the bolt with two 90˚ opposed sections of thread removed vs three equally spaced 60˚ sections and finally 180˚ threaded and 180˚ smooth. I have a gut feeling that evenly spaced interruptions to the thread will be stronger than a single large one of the same size but I don't know why.
each thread added about 10-13tons
more exciting than hydraulic fatigue testing on an MTS like I do. Huck fastners are best due to having the 'threads' hydraulically smooshed together.
This video was NUTS!!! 😁
I would love to see this test in tention. I would also like to see the test with more threads, I've been told that only the first four or so threads do work and the rest don't add much. I'm not sure if this is referring to threats that brittle fracture, or threads that yield like this.
The herzberg contours means the compression force is not optimally linear. Think about the variety of postional applications. Olams radial rule is in effect with this alloy also 👍
Found the engineer.
I’ve been watching for years now. I always knew you were nuts 😂❤🎉
Thank you so much for this. I have always wondered just how much bolts and nuts can hold in that way. Thanks.
The general rule of thumb is you need as many threads as the diameter of the bolt.
A 3/8 diameter bolt will need 3/8 of threads.
Just what I wanted to know first thing this morning! My day will now be much improved, regardless if I need to decide if a nut is strong enough for the job it's going to be used for or not haha.
How about fine threads vs coarse threads? How about a rig to stretch the bolts with the press rather than compress them - can you hold the head in place with fingers then press a nut threaded onto it with non-meshing fingers, stretching the bolt? Or would the nut fail first?
It makes sense it should basically scale linearly with number of threads except in the case of 1 and 2 threads you lose some extra because of the cupping distorts the mating of the threads with the bolt so it is easier to push through.
If you look back at single thread bolt with all threads, it starts bending around same time as machined bolt. But the machined bolt doesnt have threads beside the bending thread to catch it so it maxes out lower.
pfffff XD this was the best ad segment in the history of the channel XD
When you tested the bolt with 3 threads, I think the force meter increased after the threads failed and it exploded down. 9:20
I laughed so freakin' hard when you picked up that hot nut! I've done stuff like that before, so I'm not saying it just to be mean. Great video!
Great video! But why not have a tension load in the bolt instead of compression? That would answer question how man threads you need to reach same strength as the bolt.
Generally you are comparing shear vs tension. In some cases you want the bolt to fail before the nut. You adjust the nut width accordingly. 👍
I love The Who-Draulic Press Channel
At about 9:30, 3 full bolt threads: the force sensor peaked highest pressure well AFTER the bolt/nuts had already failed.
Only about 19.5 tons at fail
Exactly the video I hoped you’d make for a while.
When I first saw the painted nails, I was so hopeful that they were yours
This is actually a really good example of bolt strength. They all saw thread shear failure on the nut and we know that each thread can take about 25,000 lbs force.
Very nice filming , edits and shots. A big step up!
I like that he texted the nuts and bolts separately in the same video
Thread strength is ultimately dictated by shear force as long as the base material is strong enough for deformation to be negligible. You get less incremental strength from excess extra threads since bolt stretch puts most of the load on the leading threads. There is no point in having more threads what the bolt will yield at.
Fun tech called flow drilling has to answer this question with its use! In general, the first two threads take up 60% or so of the load, and it’s pretty negligible by thread 5 I believe.
The force on the threads doesn't care if it's a push or a pull, the threads would have to pull on the nut hard enough for the shaft to start necking before it would make any difference, my bet is push vs. pull is exactly the same.
Oh wow, the different numbers are so interesting
Now I know for next time I have a bunch of M36 bolts to install, but not enough nuts, and home depot is closed: just cut the nuts in half.
For a moment I thought you had fingernail polish but I quickly realized that it must be Anni. Great video and very nice of Anni to apply the cream to your face. Thanks
I've been told all my life that three full threads can take the load that is specified for any standard bolt/nut that has normal DIN thread on them.
Most genuine ad on TH-cam
I love this kinda video! You should do nut and bolt failure with measured preload and try to seperate the joints!! You can test some calculations too!
This is wonderful! This is what this channel was born to do 😁
Always wanted to see the difference between a fine thread nut and bolt vs a corse thread like fine med and corse witch is the strongest that might be cool to see in the press. Love your channel alway fun to see your experiments so cool.