Grinding a Tapered Machinery Gib using the Surface Grinder - Monarch Lathe Restoration:- Part 21

As I work to machine a new tapered gib for my Monarch Lathe, after roughing out the basic shape on the milling machine, we next want to take it to the surface grinder to put a precision grind on it to match my lathe. I will be using my Landis Surface Grinder to grind both the parallel surfaces as well as using a Sine Plate to grind a precision angle. I also have a discussion on how to calculate the angle on my existing gib and then calculate the gauge block stack needed to get the correct angle on the sine plate.
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[@RedBaron_2510]

luck wasn't a factor. the numbers don't lie. great approach to a tricky problem. great skills.

[@tjrhdeg6266]

I’m glad to see I’m not the only one who jumps when the wheel unexpectedly makes contact with the work piece.

[@dulcevendetta]

that was funny lol

[@sparkiekosten5902]

You the man Keith! That was thoroughly entertaining. I hate math but sat through your explanation without feeling overwhelmed and or bored........Keep up the good work!

[@James-fs4rn]

Nice work Kieth! Thanks

[@raincoast2396]

Thank you Keith for your time and effort, to not only bring these videos out, but also explain (what to some is a complicated process) simply and through diagrams. Cheers.

[@molaisonmaker6896]

Thanks Keith for showing us your method for determining the correct angle. Very informative.

[@phlodel]

Some comments question your methods or suggest a different procedure. There are other ways, perhaps but you got nearly perfect results. I think your methods are just great.

[@MegaCountach]

Excellent video Keith! Thanks

[@warrenjones744]

Excellent work Keith. that should scrape in with not much effort one would think.

[@johnnyholland8765]

Jeeeeezzzzzz folks give the man a break. Remember he is still learning........ Little kidding around there. He got it done and it fit!

[@argee55]

Keith, This has to be one of the best videos you’ve ever done. There might be other quicker ways to do the calculations, but this method always works for me. Besides, this is the way I learned it 40 years ago and old habits are hard to break. Keep up the GREAT videos.

[@heikkimartinoja8559]

Thank you Keith

[@rodhenry4862]

Thanks for sharing , I cannot wait to see this old girl up and running again! Great job Keith! Thank you and may God bless you!

[@noelhenderson700]

Despite the nay sayers comments, doing the math is the best way to get everything right on. I might have use the surface plate and a height gauge to get the dimensions for the ends of the gib but really, the way Keith did it works fine for the original set-up. It's a one off piece that needs to be highly accurately made and time isn't really all that important here.

[@donaldshulman6771]

Keith - thanks for the math refresher course. What other subjects do you teach? American History, English Lit, Economics? Sign me up for your next class !!!!

[@JuhaErkkila]

I quess that ten inch required height could be be calculated also by using relation without any rounding errors from going to angle and coming back... Just simply (10 inch/10,39 inch) x 0.216 inch = 0.2078 inch :) Thanks for the really nice gib video series! I accidentally broke one of my gibs from the lathe so have to somehow repair that someday. This is excellent base for what&how to do.

[@williamsquires3070]

Hi Keith. Could you use a small machinist’s jack and prop it up under the sine plate, then adjust until level with a Brown & Sharpe (or Starrett) bubble level? Then, once you’ve got that, take it over to the grinder, and mike it in that last little bit? 😏

[@63256325N]

Math....ouch, my head hurts! Excellent video for the mathematical end as well as the machining aspect. Thanks very much.

[@vincentsalerno8675]

Blue that puppy up and let’s see how she fits. Great video keep it up

[@1jtolvey]

GREAT VIDEO !!

[@ronbellaire9329]

Its nice showing the math and we all should know how, but there are apps for that.

[@darrenblattner2508]

Keith, most folks would have shimmed the old gib. You did it the right way, very nice.

[@W0mpa]

Perfect video for my morning coffe here from a wet and cold Sweden.

[@johnferguson7235]

For 80 years, my Great Aunt Sigrid started every day with a mug of black coffee and a glass of Akvavit. She baked her own bread until she was 87 years old. She always said that store bought bread didn't taste right.

[@bendavanza]

nothing like a well planned operation working out just like you wanted

[@NGinuity]

Hmm... I've been trying to figure out a slick lighting solution for my mill...then I see you've got a magnetic flexible arm LED light. I have an extra one of these that came with a sewing machine I bought. Thanks, you've helped me more than you possibly realized and wasn't even directly related to the video!

[@toolbox-gua]

Very nice!

[@bcbloc02]

I think I would have left it long until I fitted it. I would be too afraid by the time I got it right it would be too short again, it only takes a little off the width for those things to travel a long way!

[@KevinWRay]

Great Video, Nice Job!!

[@ActiveAtom]

Love the auto feed, a pair of machinists learning surface grinding for our shops future. To us if you love math you will love surface grinding. We see you are using air mist we see others using flood coolant so interesting to watch.

[@terrycannon570]

Thanks Keith. I love the detail on the math. I am in the process of restoring a Clausing model 5913. I started myself a You Tube Favorites file on lathe repair and have saved this one to it. I always love to see the resurrection of this old Iron. Thanks for taking time to share the detail of how you did it.

[@jimmymac15]

A fine lesson in trigonometry

[@chrismate2805]

A good lesson illustrating the practicalities involved.

[@RJMachine62]

Nice Job Keith - You couldn't ask for a better fit !

[@dessilverson161]

Lovely job Keith. Proper engineering. Apart from the calculator that is !!!

[@elchuco00]

OUTSTANDING WORK MY FRIEND!!

[@charlesk5519]

Awesome video Kieth. Great use of trig to solve needed stack up. You are probably aware that standard Gib taper is .250 per foot, so all the measuring of the old gib to determine angle wasn't necessary, but nonetheless was an excellent exercise and provided a great tutorial for viewers to show how an unknown taper can be determined! Kudo's

[@MrLukealbanese]

Super work Keith!!!

[@yambo59]

Great video, im just a home layman and the trig is beyond me, but looks like youre on your way to yet another finished piece in the lathe restoration - it will serve you well.

[@shortribslongbow5312]

Very nice video and another lesson learned. Thanks for sharing.

[@ron827]

OUTSTANDING math and machining! Unexpected sparks ALWAYS get my attention too, especially when working with electricity. :-) For those who may have difficulty remembering the trig functions, just remember SOH-CAH-TOA which is pronounced "socatoa". (This is the recommendation a medicineman gave to an early Indian who dropped a chainsaw on his toe while cutting wood. Yeah, it sounds dumb but it may help you remember the word.) "SOH" is sine = opposite over hypotenuse, "CAH" is cosine = adjacent over hypotenuse and "TOA" is tangent = opposite over adjacent.

[@jonka1]

The Flintstones was not historically accurate and I don't think your story about chainsaws is either. Both entertaining though.

[@BobSmith-cx4og]

Keith - excellent video as always. There was no need to use trig, just a proportion calculation: (10÷10.390)×0.216=0.2078 much simpler and quicker. This works because you have similar triangles, in other words triangles of the same shape, so the ratios of the sides are the same for both triangles.

[@clivewilliams1406]

Absolutely! KISS Principle applies here. Doing the calc using similar triangles takes out the approximation and hence the inaccuracy of the angle calculation

[@dicksargent3582]

If his surface plate is level as it should be. Using a machinists level would do the job. Especially if the first grind was only to get close as it was in this video.

[@oldschool1993]

I was thinking the same thing, but it was fun to get a trig refresher after 50 years. Looks like the cast bar still had some internal tension as it appeared to have twisted some after the machining.

[@royreynolds108]

Proportion was what I was thinking while watching and I went and got a calculator which cranked out to be 0.207892 before he got his number. I know that I took it to too many places but in rounding it makes 0.2079. I am wondering if the micrometer would not have been the better choice to start with as Kieth said his calipers are not that accurate. Just thinking. It all worked out well which is the goal.

[@oldschool1993]

@@royreynolds108 Yeah- unless you have a micrometer with ball ends, it is difficult to be 100% accurate on a tapered piece

[@garymork1380]

Keith you’re a master of you do

[@OldIronShops]

this rebuilding series we really be invaluable when i get to this point on my old 16" o series south bend

[@jerrycoleman2610]

Keith, Very Nice gib, Great video thanks for sharing.!.!.!.

[@davegower123]

Congrats on the progress Keith! Nice job!

[@SolidRockMachineShopInc]

Nice job Keith! Steve

[@ROBRENZ]

Nice work Keith! ATB, Robin

[@ruperthartop7202]

Nice work Keith

[@WillyBemis]

This is a fascinating project!

[@2listening1]

Good morning, Keith! Happy Friday and weekend to you, sir!

[@LostMountainRestoration]

Outstanding lesson! Thanks, Keith.

[@adcurtin]

Also, when using the basic trig functions, I gotta mention SOH CAH TOA, a mnemonic for knowing which trig function goes with which sides of the triangle. (sin = opposite / hypotenuse, cos = adjacent / hypotenuse, tan = opposite / adjacent)

[@skjoldhjvrkstedsforening4930]

if you do the turcite trick on that gip.. one of the sides.. you will have no bad wear on any of your parts. and u should have done that also inside at the 30 dgr angle. That would have done a hell of change in wear...

[@markreardon3472]

Thanks for the video and explanations. Very interesting.

[@stevenstagner186]

Well done Keith!

[@jamiebuckley1769]

exellent job on the taper. well now i know how you held the gib to get the angle. you used your new angle sine mag plate lol. nice to have that tool in your arsenal of tooling.

[@TheJohndeere466]

All you needed to do is put two lines on the gib 10" apart and measure the thickness at both lines. Subtract one from the other and that is the height of your shim stack.

[@theradarguy]

Keith, enjoyable video. May I suggest while you have the cross slide apart now would be a perfect time to add a couple of oil ports to lube those ways and carve some oil paths in the bible and opposing way. That would make a great video.

[@adcurtin]

23:39 "were gonna take it over to the lathe …" what the hell are you gonna do to that part on a lathe? "for a test fit" doh! I'm still laughing :D

[@Cromwell648]

Very enjoyable to watch, as always 🇬🇧

[@shadrachmalooly9394]

Fascinating as ever. Like the new title music.

[@darryldodge8383]

same music for years...

[@InssiAjaton]

While I have nothing against math and trigonometry, I would suggest a way to bypass the trigonometry steps in this case. As the reference part is longer than the 10 inches of the sine plate base, just mark 10 inches rom one end and measure the thicknesses at the end and at the 10 inch mark. The difference between these two readings is directly the required stack for raising your sine plate for the desired angle..

[@darrendean21]

Really enjoyed that Keith, nice informative video :)

[@Tf9500]

It will be nice to see the first cuts on that lathe it should be really accurate👍

[@theshaddowaust]

I remember using one of them in High school, it was great and the teacher always told us to make sure the wheel is clear of the work all along (Test run) and the guard was up too, but the sod forgot to do it his self one day and shot the peace and parts of the wheel out a window that was close to the machine and the bits just missed my self and a friend by inches. Till a few years ago when he passed, every time we saw and talked we never forget that day,. He was one of only 4 teachers from that school that understood my work ethic and loved to teach me.

[@AmateurRedneckWorkshop]

Great video and a great success as expected. Thanks for the video.

[@elsdp-4560]

THANK YOU...for sharing.

[@robertkutz]

Keith nice work.

[@ianide2480]

Love your work bud, long time sub and viewer, please keep up the great content. =)

[@grahamwright6928]

Hi Keith I really enjoy your videos and look forward to the next installment. I was always taught that you should "wring" the gauge blocks together to get a truly accurate stack.

[@BedsitBob]

I'm surprised there isn't an online calculator, to tell you which blocks to assemble, to produce a specific thickness.

[@craigleemehan]

I presented your gib angle measurement problem to my 15 year old. He said make it a right triangle and use Trig; with his tone adding the required, " You idiot." I find it interesting the number of commenters that don't read the other comments and repeat the same alternative methods of calculation.

[@geckoproductions4128]

Very interesting video

[@davidspahn7184]

First, let me say, great video, as always. I love it when I get notified that you've released a new video. BUT... (and you knew this was coming)... I just have to say that the shape of the gib is not a trapezoid. It is a parallelogram. Please don't flame this comment too hard. Thanks :D

[@jonka1]

At last someone noticed.

[@jrkorman]

A parallelogram is a trapezoid with two pairs of parallel sides.

[@jeffschira9685]

No a trapezoid is not a parallelogram. And a trapezoid is not a parallelogram. A trapezoid is a four sided figure with two parallel sides and two nonparallel side. A parallelogram is a four sided figure with two pairs of parallel sides.

[@hardkrash]

@@jeffschira9685 www.mathsisfun.com/quadrilaterals.html Trapezoids (US) are a class of geometric shapes, including parallelograms, rhombus, rectangles, and square as special cases... but not kites! Yes the most specific answer is parallelogram, but hey...

[@jonka1]

Jim Korman That's like saying that a square is a circle with corners.

[@GarrethandPipa]

left side height - right side height = the angle offset at the length of the widget simple geometry no trig needed

[@petemclinc]

KZbin puts a mascara ad in Keith's videos, they know how to target their market...

[@jimbeaver3426]

Well done, excellent results.

[@glennmoreland6457]

Hi from England I like it when maths is shown... As I have a tendency to be rather lazy when it comes to maths... I've never been much good with fancy numbers and wasn't really encouraged back in the 80s when I were at school...

[@jonka1]

That should be, "was at school". I would ask them for your money back, Glen.

[@glennmoreland6457]

@@jonka1 "Were at school" will do just fine... I'm a Yorkshireman and it's how we says it round these parts...👍

[@apollorobb]

The light you have on the grinder is the same one i have on my lathe. Sure is a big help

[@kenadams2694]

where did y'all buy it, I was noticing it too?

[@rodhenry4862]

I was going to ask that also, I'd like to buy about 6 of those light's! Thank you

[@apollorobb]

I got mine off Amazon. It's a sewing machine light

[@rodhenry4862]

@@apollorobb Thank you!

[@cemx86]

I enjoyed the math - brings back memories of HS trig class. Could the angle grind have been done using the granite surface plate, sweep the old gib with a micrometer, then add blocks to the Sine plate until the mic reads zero end-to-end?

[@laurenceporter9354]

... poetry ...

[@chuckinwyoming8526]

Keith, If the gib has 1/4" per foot taper the 10 inch sine plate should need 0.20833 (+ the 0.100 step). This is within 0.001" of your stack and you will be scraping anyway. Just nit picking I guess. Great job on the video.

[@johnapel2856]

Great video! I would have liked to see the math the second time, but understand it would have been repetitive and probably boring for many viewers. Thanks.

[@CrimFerret]

Neat video. One slight issue with the math. You can't get 4 significant digits after the decimal if your measurments were only taken to 3. It would have been correct to round the height to .208. It won't matter much, since the gib doesn't actually have to be accurate to .0001 (or you'd have used a micrometer). Just wondering if you could have gotten just as good a result with a precision level.

[@harlech2]

Keith had to change his underwear after he made first contact with that gib, LOL

[@markschweter6371]

Qjuestion: Since you're trying to make the first two faces parallel, How do you assure the workpiece isn't warped by the magchuck as the seating face is only milled "flat"?

[@govertical72]

So cool Keith, question? Did you account for keeping gib perfectly parallel with direction of grinder? Not sure but seems like that would change the math if it wasn't parallel.

[@Looptydude]

I probably eyeballed it the best he could, the scrapping will take care of it anyway.

[@schmu79]

I was thinking the exact same thing. The angle won't be correct if the gib isn't parallel with the direction of travel. For example, if you turn the gib 90 degrees, then there won't be any angle along the long length.

[@adcurtin]

the angle bracket-like piece at the end of the sine plate is up against a flat piece (though small) of the gib, so that should keep it fairly close, and scraping will take care of the rest.

[@tupperwallace9048]

If you do the math you’ll see he’d have to put it on the table really slanted to have any significant error.

[@lwilton]

I wonder if the stack really should have been slightly different. The measurements you came up with work out to about 0.249 inches per foot. I think it is reasonable to assume the design taper was 0.250" per foot. sin(atan(0.250/12))* 10 = 0.208288, so the stack would be 0.2083. Of course since you tweaked it to match the machine it doesn't really matter.

[@royreynolds108]

I think you are correct but with all of the wear and scraping the measurements changed over the years.

[@SuperAWaC]

since it's not a variable thing couldn't you just mark 6" on the gib, sweep it with an indicator on a surface plate, then have your thou taper per foot?

[@melshea2276]

👍

[@jerrycoleman2610]

Keith, WOW what a great job I see on your new gib.!. One question though, now that you have your tail rest & center rest, will you get the pneumatic tapper attachment working and in stalled.?.!.!.!.

[@totensiebush]

I have a question regarding the math there. .2078 over 10" works out to .24936 per foot. I suspect that the actual measurement was .25000 per foot. Do you ever check your measurements to see if they're very nearly a logical number?

[@newandoldtech5634]

At 11:30 why not put the old gib under the new one in reverse and the result should be flat. Mag them together.

[@steveskouson9620]

Keith, since your pivot and the other end are 10.00 inches apart, why not just measure the fat end of the wedge, and then, measure 10.00 inches away, towards the thin edge? steve

[@leiferickson9666]

Keith, I do not like just mag., on part with no support on ends, and sides. You can get an assortment of desperate mag., blocks, to block your work pc., in, so there is no accidents!!! You can get blocks as required, it's much safer, believe me, I ran a surface grinder........🍁

[@leiferickson9666]

This word correct thing, sucks, remove desperate!!! 🍁

[@leiferickson9666]

Just check it for oil groove purposes, it's done!...🍁

[@raymond80hr]

what did you make that out of the get orange sparks

[@johnleake708]

Why not use the short gib as a template and lay the new one on top (opposite small end over large end) on the magnetic vise? That would provide the angle as the old one was ground? I understand the need to know how to calculate it, however in this case you have a template to grind from....

[@jonka1]

I got the impression that the old gib was worn in the middle. The magnetic forces would have pulled the new one out of true and produced a faulty grind.

[@noelhenderson700]

The original gib angle wasn't quite right which, along with the fact that it was too thin is the reason for making the new gib. It can be used to get the angles close but once that is done you need to fine tune the angle until it's right on dimension.

[@jmwarden1]

Keith, doesn't it make a difference as to where you put the stack of blocks?

[@michaelshea5427]

Lost me at calculus! Haha. No, i loved watching you do the math! Could you have indicated the taper in to 0 on the old gib and then added a few thou to account for the wear? Just asking and not giving advice as i have no clue how to do this! ;)

[@stevef01]

Safety glasses?