Grinding a Tapered Gib for a Metal Lathe
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- เผยแพร่เมื่อ 11 ต.ค. 2020
- Grinding a tapered gib for a metal lathe on the surface grinder using a compound sine plate.
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Hey Keith, got the gib back today. Beautiful job! Took about an hour to trim, fit, and put it all back together. Works perfectly! The taper must be exactly right. The pressure is the same throughout the range of movement. Thanks so much.
I believe this is all a silly misunderstanding. That's not a gib. It's clearly a tapered bastard file.
It's funny (to me) these folks go on about scraping marks as being a good thing then when they get something with loads of scraping marks, they complain. Just get the thing fitted, the high spots will ride up with wear !
Like bush bearings - make them a little tight and let them polish themselves in use !
Best bumper music in the business.
Gib is maybe the least word-like word in the language.
I believe Stefan Gotteswinter has stated that he considers Chinese machine tools to be "kits", and I have had a similar experience. I purchased a Grizzly G0602 lathe five years ago (my first machine tool). Over the span of the first year as I came up to speed I discovered several issues which needed attention, one of them being the cross slide ways were .006" out of parallel from end to end. A local machine repair shop was able to reduce that to .001" by truing one of the surfaces, and it works much better now.
But hey, it was a $1300 dollar lathe, and it works well now!
Jason, I fully agree with the thinking that Chinese machine tools can pretty much always be greatly improved by the owner doing some fettling and adjustments. If you get as involved as Stefan does with hand scraping ways,surface grinding Gibs etc the end results are truly fantastic.
I just think it is wonderful that you help people get their machines running well. I really like watching these episodes!
Enjoyed Keith!
ATB, Robin
Thank you Keith
Great work Keith, thanks for sharing
Thank you Keith for the comments about this supplier. With as much advertisements they send me, I’m quite surprised. Another excellent presentation
THANK YOU...for sharing. Watched and very much enjoyed.
Perfection once again!
Thanks for sharing!
Very cool of you to take it on. Made for good content.
Did they send the gib with the note "some work required"?
What the hell...
Nice video, Keith.
Someone sure dropped the ball.
Good recovery.
Thanks,
John
Great video mr Rucker all the best stay safe god bless
Thanks. Enjoyable to look over your shoulder. Appreciated.
So much or Grizzly's customer support. A nice rescue job Keith.
I think replacement components such as this should always be viewed as needing finishing to suit the individual machine, but I'd expect a better finish than that to start from, with at least a ground finish. I mean from here it looked like an old file that had been trimmed to size with a thin cutting disc in an angle grinder at the start!
very good keith
Hi Keith, I can see ladder marks on your grind. Probably should be balanced.
I bought a gib from Jet and was exactly the same, rough milled and not on size (a lot thicker than it needed to be).
Grizzly did that to me as well. Great Episode Thumbs up!
I bet This Old Tony is taking notes right now 😁
shipped as cast!
Nice grind Keith. That should work well.
Almost all the machines in my shop are grizzly, most being over ten or more year old. I only had to buy part once during that time, I got it quickly and it was the right one. I have very happy with the quality of the tool. Do they make a bad one ounce in a while, yes just like any other manufacture. Grizzly tool are good tools at less then the price of the premium brands.
I'm not surprised at all I've ordered parts from Grizzly and that's what's I've received too.
Same, they usually send replacement stuff to me for free though
So I kind of take it for what it is
Nice!!
Grizzly expects you to finish it yourself because there is no way they can know the condition of the item being replaced. It is NOT a bad part. It is the ‘raw material’ you needed. So what if it has a lousy finish. As usual, Keith did what was right, to good effect.
Definitely semi finished machine tools on that part!
I have been suspicious of Grizzley Products for a Long time --This make me sure Im on target !
There junk....there only for people who.dont know any better
Great job as always Keith, it's kind of sad though this makes me want to sell off all my grizzly equipment quick fast and in a hurry before any of them need parts
Good morning from St John Parish, Louisiana 12 Oct 20.
They're supplied like that so they can be finished to suit the machine. That's why they're oversize in every direction. TBF there's very little point grinding something that's going to be ground again.
I’d like to see an update to this as to how it worked out
In UK mechanical engineering there are many types of key, a gib is the only one with a head!
Yup, gibs or gib strips when applied to the adjusted bits in slide ways !
"Grizzly" is a descriptive term, perhaps appropriately applied to the Grizzly brand as witnessed by this video.
or maybe the gib was mauled by a Grizzly?
Must be a Grizzly part, that's how all of their stuff looks.
my home shop is incomplete without a surface grinder.
My century old Mueller has an issue where the cross slide tightens as it moves in, and when it's out, as it would be for large diameter parts, the gib is at the end of it's adjustment and barely tight enough. I suspect that the machine was used in the production of something that required a lot of facing, and that for many years. The cross slide dovetail, on the carriage, measures across pins to have less than 0.001 variance. When I took the cross slide apart to check/clean it, I discovered that the upper section had been milled, and the gib appeared to be the original.
I'm feeling great reluctance about going further down this rabbit hole, but it's going to get me in trouble if I don't do something. If the gib tightens up while under power feed, it becomes difficult to disengage. Increased crash potential, and more than normal stress on components in the apron. Like it or not, I see finer metrology, stunt grinding and possibly scraping in my future.
Reckon they got the local blacksmith to forge that gib!
Hiya Keith
I gave up on Grizzly 2 years ago after purchasing a small English wheel. It is flimsy and out of alignment, assembled with quick and cheap methods. They offered to replace it quite readily. Getting a replacement of the same quality is not my idea of customer satisfaction. This is probably why you got this project as that quality gib is most likely all they have. The owner will have a quality gib once you are finished redoing it, for sure.
By saving up on the production of this gib, they hired a guy to come to his house to throw they gib at his head and scream "there's your f***ing gib, you piece of s***! Don't call us again!"
Sometimes their parts are very high quality in finish, and sometimes not. But at least they do stock lots of parts for older machines. Many suppliers have virtually no parts. You’re completely on your own.
It isn't uniquely a Grizzly trait for the Gib strips to be as rough as a bear's backside (pardon the pun there) . I've witnessed several other brands of Chinese lathes and mills where the machined finish of the taper gibs left a lot to be desired. This should be a vast improvement over the original broken and bent item.
I guess this was filmed before you got the taper caliper?
What’s most you can take off per pass on a surface grinder?
Well, I don’t think Grizzly are basking in glory with this one, but I tried to order a spare shaft for the cross head feed for a fifty year old Swiss made lathe. The company still exist though they don’t sell my lathe any more. The company regretted they didn’t have any old stock spares, but it was a simple part, they would be happy for me to machine my own copy.
I once had a Grizzly 9" lathe. Not a quality machine. It went through 3 motors before one would keep working. Not surprised about the gib.
👍🏻👍🏻
What wheel did you use?
I’m commissioning my grinder this week and need to get a variety of grinding wheels.
Others can chime in here, as well.
Thanks again,
John
You should have ground the first side at a static state then use your magnetic sine table.
First let me say that I have owned GRIZZLY gunsmith lathe for over 7 years and I am 100% pleased with it. I also have a bandsaw I like very well. Now, I recently ordered a spider for it as they were on sale. It arrived in original packaging from manufacturer, NOT Grizzly, and was missing all four adjustment screws. So, I contacted Grizzly customer service and they said send whole unit, in original packaging, back to them at my expense and they would refund my money. I went to the hardware store and purchased the four cap screws for about $5 and told them about it, but got no response. Grizzly is not about customer service, it is about acceptable (not best)quality and lowest possible price. Their C/S is least cost automated customer service. Real C/S requires knowledgable people, and that costs money. I have dealt with middle eastern and Indian businessmen since the 80s and it is my experience that they will never out and out steal from you or cheat you, but you will NEVER receive more than you pay for. Grizzlys business model is designed to not waste money foolishly on C/S, but to just offer whole unit subassembly replacement when warranted and let the customer worry about it. Will I purchase more machinery and tools from Grizzly? You betcha. Do I expect first quality? I would love to be surprised. IMHO from South Texas
Grizzly....you have my sympathy
I’ll tell you, I bought a 3hp cabinet maker’s saw from them shortly after they opened their doors about 35 years ago. The righ T slot had a spot filled in the casting from a blowhole. A little bit of homing and it was fine. The arbor was also out by 0.005”, which isn’t great, but no worse than a number of other makers, including a couple made right here. I took it off and took a bit off the back collar with my (Southbend FOURTEEN, which I did refurbish, though it was owned by an individual who bought it new, and was careful with it, not a shop) where the blade rests, and it’s became 0.001” off, which is about close as any machine gets. Other than that the machine as been 100% reliable for all those years, and it gets plenty of use with thick woods, 1.5” aluminum, plastic and thin steel. No complaints here!
I also have a mill from them I bought in 1998 that also gets a lot of work. No problems there either, though I made some mods.
I have some other equipment as well. The cheap equipment is, well cheap, but their better stuff lasts a long time, and works very well. I’d be curious to know how many people here can truthfully say that they bought new American made lathes, mills and other equipment for themselves. Not many I can wager. And old, used American equipment, from my experience, tends to be worn out from use in shops that really don’t give a damn about taking care of their equipment, unless you’re the rare one who gets really lucky, as I did. They get rid of it when they can’t meet customers specs on it, and then amateurs buy it. Since almost no one can refurbish their own machines, and pro work often costs tens of thousands to do, that old, and often, junk is just used.
I’m not impressed.
Is that just fine mist of water?
You Buy Cheap You Get Cheap
some modifications fitting required ready to go from the factory
I have quite a few pieces of Grizzly equipment. From what I’ve seen, the woodworking equipment is significantly better quality than the machining equipment. The benchtop metal lathe I got was pretty abysmal. Had to mill a new front plate for the compound as the compound leadscrew nut and faceplate mount for the leadscrew/dial didn’t line up so the compound would bind up badly at that end of travel. In taking it apart to repair that I was disappointed to find the compound and crossslide ways looked like the finish on this gib. Nice surface grinding on the exterior of these parts but butt-ugly mill finish inside. Scraped things clean (amateur job) to get a functional machine, and have been using it to get a 1944 Monarch CK lathe cleaned up.
So in the end it was good practice toward getting something really useful. Machining is a challenging field to get into as a hobby. As someone else said you just about need a complete machine shop to start. It is great that you’re helping folks out Keith.
I think this was quite unfair to Grizzly, and perhaps even a bit rude. Stefan Gottswinter has a video about fitting a new gib to a Schaublin lathe -- certainly a high-quality machine from a reputable company -- and that gib need to be fitted quite dramatically, too. Stefen didn't show much surprise, he just settled in and did all the precision work to fit the gib, and things turned out quite nicely well. It will be impossible to fit a gib with precision if you don't have the dovetail it fits in, and each one of those is as unique as a fingerprint! And obviously, if you're going to have to machine all four sides of a gib to properly fit it into its dovetail, it really doesn't matter what the original surface finish is.
I think part of what we're seeing here is the difference between a machinest who is very good at "getting things done," while minimizing the cost and the time involved, versus one who leans more toward high precision, which is always going to take longer and cost more. Personally, I would prefer the former for production, or a project that doesn't require high precision and should not be allowed to consume all available time, but maybe would prefer the latter for the details of my machines and so on; the basis of my precision.
So was this gib already through hardened before grinding? Do gibs even get hardened? I need to make one. Does anyone know where to start? I have access to a surface grinder and all that.
Not sure what anyone expected from grizzly
What keeps the gib from sliding off the table during the grinding?
Will the magnet distort a thin piece of stock?
Yes it will distort the metal, magnets are very strong.
ha - something to watch :)
Is the grinding wheel in line with the X axis on these type of surface grinders ?.
It should be...
Did somebody misplace this part in the gib drawer? Maybe it's intended for a totally different use?
8:09 - How would you grind that ski-ramp anyhow?
A question to the community. I've got un unboxed magchuck, some 6" by 10". Could it be used tied to the mill table for light milling works of magnetic materials? Anybody tried this?
I've taken my mag chuck off the grinder and used it on the milling machine. It help to hold some really awkward shaped parts. And as you say, just for light milling operations.
@@fredbloggs4829 Thanks a lot! Then it's worth unboxing and degreasing it. Sometimes usual clamps can't be used so the mag chuck opens up for some new kinds of work.
What material is a gib normally made from?
'Rough milled'? That things a dang corse file! And you just know it was some kid with an MBA who said "Just send them some scrap metal for thier money and a brochure for our newest lathe and CNC line!".
Yeah, what do these kids know today. When we were their age we already knew everything!
0_0 my face at 12:26 when i thought you were taking a .025" cut on the surface grinder
Hello! A newbe question if I may? How do you determine the size of a surface grinder? is it as big as you can put in the shop? also manual run or hydraulic operated ? also I am concedering 3 ph your thoughts please I really enjoy your videos tnx Dan
That piece looked real Grizzly . Now watch the post bend them into a pretzel .
What exactly does the diamond "dressing" bit do? Maybe removes any embedded debris or roughens the surface?
Removes a bit of the abrasive. In doing so, this removes any dull areas, embedded metal/debris, and out-of-round areas. Wheels are considered consumable for a reason.
In addition to what Larry said, the diamond's primary purpose is to make the surface of the wheel square and flat to the surface of the plate. Like he said, the wheel "consumes" itself as it's used and over the process of grinding, it will develop grooves and become uneven and out of square and you need to use the diamond to true the wheel back to square periodically.
I'm guessing that gib is metric and tapered 8.5cm per meter. That is a slightly larger taper than the usual English measurement of 1 inch per foot. I have to wonder if the tapers were developed independently, or if one was a rationalization of the other.
Can't help wondering if the reason the end is 5 thou high is because it's not been worn as much. Maybe you should have used that as your measure not the main part and you've ground the gib to match the wear pattern of the old one. Just speculating.
grinding while blind, with that being said, without the machine in hand to check the fit. luckily the piece of scrap is longer than the original.
Question Is there an attachment to convert a milling machine to a surface grinder? Have a milling machine that needs the bed resurfaced. Thanks
It wouldn't work unless the ends of the bed will travel past the center of travel. Also, if the mill is old, and the ways aren't dead flat, you'd clean the surface, but the bed could be high at both ends.
@@componenx Thanks for the info. I'll pass it along to the person who owns the mill It is old and the surface has a fine surface rust Again thanks
@@karlgoebeler1500 if it's just rust he wants to remove, I'd use a towel soaked with evaporust, or if he has access to a large surface plate, he could glue emory paper to it, invert the bed and "surface" it that way.
@@componenx Personally I'm into electronics I would not have thought of this variation in repair. That is why I asked the question. Think I'll "motivate" him in that direction. This machine could be a 10" x 40" bed' Again thank you for the information.
So basically you need a complete working machine shop, to fix the replacement part, to get one of the machines up and running?
Very interesting video with meticulous work, however I would like to know what a GIB is and where it fits on a lathe.
Brian - Google and TH-cam are wondrous when it comes to info. Just type the word 'gib' into the search bar and be prepared to get "edumacated!" This goes for just about any question you may ever have about anything!
@@peterhaan9068 Can we get you on a TV quiz show, specialist subject "The Bleedin' Obvious"?
@@brianjonesg8aso403 Obvious you ain't and bleedin' you are!
Couldn't you have placed the new gib on top of the old one and stuck it on the surface grinder? It seems like that would have replicated the angle perfectly.
I think the old gib was bent. In any case, if one has a sine plate to their disposal, for a job like this, it's a no brainer.
@@ratdude747 That makes sense.
There seems to be a general trend here to bash Grizzly products. This stuff is all made in China, the final quality can be hit or miss. I have a Grizzly belt grinder and a buffer. For 25+ years the motors of both have been running smoothly and quietly at a 1/4 the price of a Baldor motor.
Keith, would you be willing to rough me out a 19 tooth blank of a worm gear? I have an old 1984ish taiwanese 12" lathe i bought for $300, and the power feed worm gear has a few smashed teeth. I have no means to index 19 times on my benchtop harbor freight mill 🥺. I do have the hob to finish the gear in my lathe though.
Do you think they are rough machined ready for grinding? Did your viewer speak to Grisly and give them hell!
Very likely. Most of the Chinese machines are built with very old techniques, and require a fair amount of fitting to get working correctly. "Fitting" is an abbreviation for "File, Grind, Machine to Fit" a.k.a. Git'r Done. I'm not bagging on the Chinese machines: they are fairly accurate; For how long will they retain accuracy between rebuilds is the real question. I don't see too many Mainland Chinese Made machines being used as "daily drivers"... those that are, don't seem to hold up too well.
7:45 Do you think that 5 thou rise was deformation from whatever impact caused the end of the gib to break off?
That was the new blank.
Would there be any real benefit of putting a scraped gib in if the castings it goes inside are not straight and scraped?
Nope.
Oil retention.
@@littleworkshopofhorrors2395 On a Grizzly Lathe? It's like trying to make a pair of suede shoes from a month-old road killed deer. I don't think you would find a machinery service that would be willing to scrape a Mainland Chinese-Made Grizzly lathe in.
@@matthewhelton1725 true but that wasn't really the question.
My chinese mill has "scraped" gibs strips but it looks like they were scraped with an angle grinder! There's a quality for you.😢
Scraping and Flaking are two different things. They relate to one another, but scraping is done for flatness and even wear over time. Flaking is specifically for oil retention.
Could it be that the manufacturer assumes the end user will finish the part? Jet didn't have the machine and didn't know its state of wear so they couldn't send a part that was made to fit out of the box any more than you could grind it to fit without the machine. Setting the customer's expectations should probably be worked on but the condition of the gib as received might have been intentional and not just lazy....maybe.
I knew that mail was slow, but if you just recieved something from George Wallace, its a lot worse than I could have imagined.
This comment is to sort out the "mature" viewers!
You win the comment section! Hahah
Lol
That 5 thou kick on the end had me a little worried that youve ground it to some arbitrary worn size and not the original size of 5 thou bigger.....
Alternatively, that was the end the gib was broken off of. In snapping it off, it could have bent the original. Very possibly a fixed attachment point near that excursion, acting as a fulcrum.
The company's called Grizzly? They sure live up to the company name. Rough milled finish (probably 20+ micron), what looks like stock surface on the non-tapered areas, longer than what's needed, burrs that could cut you open. Yup, sure looks like a grizzly piece.
FWIW I can tell you a brand new gib from Hardinge for an HLV-H requires trimming to the correct length, let alone scraping, and their cost is a significant portion of the cost of a Grizzly lathe. IMO there should be no expectation that a part of this nature is a simple R&R from any US OEM, or some factory in China that produces lathes for numerous importers/retailers.
Are you not afraid the magnet will pull the gib out of wack?
After reading through the comments, especially those with experience in Grizzly products, I am left to wonder if that piece sent from Grizzly was simply a rough blank - and meant to be ground to fit just as Keith has done here. It appears to be their "MO". Is that a smart business move? From a user perspective - hardly. From a manufacturer's - dunno, maybe?
Unless the manufacturer assumes the end user realizes that the gib is going to *have* to be fitted, because every machine's circumstances will be different. And in that case, the user would treat the replacement part as stock, of the right material, slightly oversize, and go from there.
You must keep in mind WERE it came from!
"WERE"?
I wish he would explain why he doesn't use the old gib as a "shim"for cutting the new one. Put the new material on top of the old. You then have the proper angle. Cut to length and width prior to tapering it.
But how do you want to hold it? The magnetic field won't go through the original gib, if you want to grind it this way it will just get shot out by the wheel. You also can't clamp it because you have to get access to the whole surface.
@@CatNolara thank you for the explanation. I was thinking that if they were the same with they could be held in a vice with proper shims underneath. But that's way more complicated and probably wouldn't even work. Thanks again
Keith, I have the utmost respect for you and your techniques. Your willingness to help others is outstanding and your videos are a pleasure to watch. However, I feel that you need to be a bit more precise about describing a sin bar. For very good mechanical reasons it's not a tan bar. I know there are special machinists' names for the sides of a right triangle, but for the sake of this argument lets call the three sides rise, run, and hypotenuse. This makes the most sense when the sin bar is mounted on a horizontal reference surface. The distance between the centers of the sin bar's cylinders is the hypotenuse. I think you said that distance was 10" for the B&S compound bar. The rise is the thickness of the gauge block stack under the front cylinder. I think that most engineers most of the time define taper or slope as rise over run, not rise over hypotenuse. I know that when you measured along the tapered surface to determine the slope, you were actually measuring rise over hypotenuse so the "taper" was what you needed for a sin bar. I just don't think that is the normal definition of "taper", at least outside the world of machining.
I am a physicist by training, not a machinist, so I might be wrong in all this. If so, you could do me a huge favor by correcting any misconception that I might have here.
Sine not sin.
It doesn't matter at all since you aren't using 90' as a reference. A taper is a taper no matter if its referenced on the long side or short side in this case as its only a reference to a thickness over a determined distance and not from a 90 degree starting point
@@toddkratzer7953 , I suspect you are right. The expression sin(x) means the sine function applied to x.
@@thecanadiantradesman7916 , OK, suppose you are machining a tapered pin out of bar stock in a lathe. Is the taper the change in radius per unit of distance along the rotational axis of the pin or is it the change in radius over the outer surface of the pin? I'm pretty certain it's the former instead of the latter, since as a machinist you would not be able to measure the length along the outer surface until you had removed the metal above it. In less precise terms, the distance along the ways of the lathe is the run and the radius is the rise. That's tan(x), not sin(x). For small x, the difference is small. However for a Morse taper or a pipe thread taper, the difference is pretty substantial.
Sorry to be such a stickler, but machinists need to understand this.
Whenever you go to a sin bar, be sure to have a lot of $1 bills.
That thing was more of a gub.
Maybe that was a gib blank. Meant to be machined.
If that's the case, why bother with the rough machining before sending it out?
I'd hope they consider that gib a blank, but how many hobbyists have a surface grinder to finish it? Ok, I do, but I'd be PO'd if I was expecting a usable part! I'd accept a free Grizzly machine, but I'd never buy a new one!
4:00 Why all the maths, Keith ? Surely, if you want to copy that taper, all you need do is mount the new one on top of the old one ?
Always a great show with Keith Rucker. Sad about Grizzly, but that seems this country is turning into a production company and to hell with quality.Our Founding Fathers are turning over in their graves. Oh well.