Grinding and Milling Flats & Dovetails on a Lathe Compound - Monarch Lathe Restoration Part 23

More work on the Monarch 16" Model K lathe restoration. This time, we start working on the lathe compound by grinding and milling the various surfaces in preparation for scraping. The bottom was surface ground on a surface grinder and the dovetail areas were milled on the milling machine using a dovetail cutter.
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[@leriksenbendigo]

so many videos in 1 week - its like Christmas and you're Santa !!!

[@MaturePatriot]

Great work Keith. Can't wait to see this old iron running again.

[@d6joe]

Just used your discount code for a 30 hp phase converter.

[@edsmachine93]

Nice work Keith. Thank you for sharing the process. Take care, Ed.

[@OldIronShops]

i hope that you continue with the rebuilding videos once you finish this machine this is very valuable content.

[@rodhenry4862]

Thank you, thank you, for all you are showing and teaching some of us that are retired and starting out with old well used machining machines! I've learned an awful lot from you Keith and other you tubers ! I wish I had learned this earlier in my life! But my wife always knows where to find me now..lol Again Keith Thank You!! 👍👍

[@63256325N]

Thanks for the videos.

[@needleonthevinyl]

This video was only titled "Grinding and Milling Flats & Dovetails on a Lathe" on my home page, and I was real confused for a second. Great video as always.

[@JourneymanRandy]

Nice work Keith

[@ROBRENZ]

Looking good Keith! ATB, Robin

[@RRINTHESHOP]

Nice, lots of wear. Real nice milling.

[@uberintj]

Getting his use out of that dovetail cutter, eh?

[@SolidRockMachineShopInc]

Good job Keith! Steve

[@jeffkling7589]

Man, I love the grinding.

[@iiredeyeiiredeye1569]

Hi Keith, great series on the restoration of the Monarch. I hope you don't mind if I add a point? I noticed that you carefully ground the bottom of the compound slide working from the non wearing top edge of the dovetail, and then reinstated the reference surface which cleaned perfectly to prove the bottom surface was perfect. But then you placed the part on the mill and re-machined the dovetail using the bed of the milling machine as the new reference. I think this was a mistake...I feel what was needed was to mount the part on a adjustable angle plate and dial in your reference surface and machine it from that. Thus eliminating any error in the bed of the mill. As it turned out you had a small run out of a thou or so, but I do feel this could have been all but eliminated had the part been dialled in from the newly ground surface. I hope you don't mind me adding my point of view. Thanks for a great series and channel. Best regards from England. Richard

[@ActiveAtom]

I watched a lot of grinding going on over at Solid Rock this morning while he and the family make you that special boring bar. I am ok watching some more grinding here as well, you are after all rebuilding a machine nearest my wants list, not the one but close we like the (we heard you have one) 10EE. Dove Tail cutter by? lol Love the twin dowel pin dove tail measuring lesson, real good outcome.

[@elsdp-4560]

THANK YOU...for sharing.

[@piast99]

Nice job! I am very anxious of the final result. It is going to be the most precise Monarch lathe in the known universe, I just wonder if the relief at the bottom surface was important and if it should not be restored back. Maybe it was designed to contact only on these two rings but not around the clamping screw hole.

[@oldschool1993]

Probably just a minuscule thing, but you have a reference mark on your compound which matches a reference scale on the carriage for setting your angles. Ideally you would have mounted the carriage to the mill and dialed in the dovetail, then set your reference mark to the zero on the scale and ground the compound dovetails from that point. But for all practical purposes, the angles will be close enough for most work, and any super precise stuff would be done by dialing the compound to the spindle.

[@antonionunes7522]

parabens

[@bcbloc02]

You probably have already done the work so it is too late to help but since you did the compund ways and dovetails together and they appear to have good parralleism I would flip it and regrind the bottom using those surfaces as refrrence to knock that thou off and save a bunch of scraping.

[@mikebowling3228]

Keith, I believe you should have had your dressing diamond holder rotated 180 degrees. Be sure to rotate the diamond in the holder occasionally to keep the diamond sharp .

[@jhueth3969]

I like to scrape the top slide real flat and then use that as the master for the lower.

[@mariothegreat4197]

im milling dovetail allmost every week and i can say its pretty much impossible to mill something perfect but being within 1tow is very good, my usual dove tail are 28 inch long and im happy if im within 2 tow

[@markschweter6371]

Question Keith: I dont remember, did you also check/grind the compound's mating surface on the cross slide for flatness and parallelism to the ways?

[@jerrycoleman2610]

Keith, great work on the compound slide sure can’t wait to see the old girl running, will you try and get the tapper attachment working too..!.?.!.

[@vettepicking]

Looks like that mill should be next. .....lol

[@jeffreymurdock8366]

It may seem crazy but I could actually see the difference on those dovetails

[@WillyBemis]

Thanks Keith! Sometime would you show us how you lower the grinder 0.001"? It must be a very interesting mechanism that can be adjust so precisely while the machine is running.

[@zHxIxPxPxIxEz]

If you mean "one tenth", that's .0001 It depends upon the grinder. Some have "picks" which are separate dial/cranks that let you with the gearing they have down feed one tenth. Most grinders just have a large handwheel graduated in tenths with ever 10 tenth being a large mark going up in .001 (or one thou)

[@zHxIxPxPxIxEz]

Clear as mud?

[@pontoonrob7948]

Is there such a thing as climb grinding and conventional grinding? If so, do you get better finishes in one vs. the other?

[@scottyt187]

One question -- shouldn't you press that center swivel pin back into the compound? I suspect the pin will end up bowing out the middle of the dovetails a 1/2 thou or more. I would at least press it in and reinspect for dovetail parallelism to see if it changes. Just my 2c for what it's worth...

[@lindsayfog5246]

I know you ground your chuck in , but did you grind in your magnetic parallels ?

[@kakiller]

i was thinking the same thing.

[@lindsayfog5246]

then I thought nah, he would have checked them. anyway it's easy to take this sort of thing as a 'how to do it' rather than 'how I did it' , and he's doing a good job. everyone will do things differently but the job will be pretty much the same.

[@eatonasher3398]

Where did you get that dovetail cutter?? I want one of those!

[@ericmcrae7758]

#1 you sure need some patience to get this right

[@theworkshopmechanicchannel3296]

Eric McRae If one isn’t married or doesn’t have the IRS on there back then it shouldn’t be a problem 😂😂

[@mtraven23]

i'm working on a shop built power scraper...could anyone advise what the useful range of strokes/min would be? also my design allows for stroke adjustment from 0-0.75", that should cover me, right?

[@crockteerden4023]

Are you concerned about the center line of the screw.

[@jusb1066]

im sure he intends to use an adjustable quick release post , a bit of height loss is adjustable on those

[@xenonram]

@@jusb1066 I think he's talking about the lead screw that translates the tool post across the compound.

[@patrickdarcy3863]

You have to be careful when re machining the dove tails that you do not off set the lead screw so it binds.

[@PikemanLures]

Why did you worry about climb vs conventional milling with the dovetail cutter on some passes but not on others?

[@phildcrow]

I think the dovetail passes were conventional, but milling the flats has forces just wiggling the tool in a circle, so less care needs to be taken. I say that as a total noob.

[@PikemanLures]

@@phildcrow This is true, you are correct

[@bogartaspen]

Keith:I'm a retired tool& die, machinist. You continue to use your finger as a pointer around a running grinding wheel and milling cutters. I did the same thing for years then I had a microsecond lack of attention and I put my index finger into a 1/8" wide milling cutter and cut a groove in the finger. To my dying day I will remember the sound of my finger being cut like a butcher cuts meat!Please stop and think what your doing!

[@bobvines00]

Keith, I've got a brain-dead question this morning about the milling you did in this video. Do you ever need to do anything with long cutters, like your dovetail cutter, similar to sparking out on a grinder? I know that you really can't take too small of a cut or you'll just smear/glaze the surface even with a milling machine. I think.... :P Could deflection of your dovetail cutter be responsible for the slight lack of parallelism you had to scrape out on your compound? I hope that you and your family have a great Christmas and a Happy New Year! And that you are able to do a lot of "playing" out in your shop during your holiday vacation.

[@Fabes002]

Hey Keith, I'm getting ready to begin building my shop. Can you come and help?

[@currentbatches6205]

I hate CI chips! A rare-earth magnet in a plastic bag will get most of them from a mill cut. And aluminum foil 'pan' under the chuck will get most of them from the lathe. Holy cow! I wish I ever had use of a lathe as zero'd as what Keith is doing!

[@jamesrawlings8493]

When the lathe was new, what tolerances would these parts be made to? Are you milling it to be more accurate than new or just fixing wear?

[@jusb1066]

im sure even in the dark old days they could manage a thou, after all its a lathe, not a ditch digger. most were used in auto manufacturing and i dont want my parts with sloppy fittings.

[@sarahwatson7692]

James Rawlings In the early 20th century hand scraping easily produced tolerances of .00001. Really skilled machinists could achieve somewhere around a millionth of an inch.

[@mikharienmetalworks8498]

Why ..you do grinding first not mill dove tail first..?

[@mathankumar6473]

Newbie question, why you need scrape it when Its 1 thau parellal/run out? I guess 1 thau not bad at all, and why you still need to scrape?

[@noelhenderson700]

When time doesn't matter much and you want to get as close as possible scraping will get you there.

[@deathk26]

This question has been answered numerous times in both his videos and the comments. While scraping won't get you a perfectly flat surface (you don't want that anyway) the tolerance will be a lot tighter than a milled surface. You want tolerances within at most a few ten-thousandths of an inch for these applications. Scraping also creates minute voids where oil can collect providing better lubrication. The sliding surfaces also won't bind up or lock due to excessive static friction like they would if they were perfectly flat. You should watch previous videos of his on the scraping process if you want to learn more.

[@googacct]

I am really liking this series of videos. Why is there .001" difference in parallelism for the dovetails. Is it cutter deflection or did something with the mill or part shift?

[@jacilynns6330]

This may be a stupid question but wouldn't it be better to scrape a worked surface than a ground or milled one. The act of grinding or milling cast iron would expose softer metal. What I mean is after a short amount of use the soft areas would depress leaving you out of square again. Just a question.

[@xenonram]

You can't scrape a "worked surface" if it's not already pretty flat/parallel. If you did, you'd end up scraping away the worked surface anyways. And it's a lot easier to getting then scrape, rather than scrape an uneven surface.

[@jacilynns6330]

@@xenonram i understand the concept but i dont know my intuition is telling me that something has been overlooked.

[@AbbeyRoad69147]

Your clamping deformed it elastically. That is why the milling has 1 thou runnout IMO. Try clamping with magnet and mill again 1 thou deep. Then it will be flat.

[@hankthebugman]

Paul Sheer I wondered also why it was out. Only reason I imagined was deformation caused by clamping forces. Keith did not seem concerned.

[@shadowdog500]

It is going to be clamped at those same exact bolt holes when in use.

[@4GSR]

Nothing to do with how Keith clamped it. That's wear in his cross slide on his mill showing up on his work piece. Still not bad! Ken

[@AbbeyRoad69147]

@@shadowdog500 hmmmm... good point

[@4GSR]

probably so. To me that's no big deal, a couple swipes with the scraper and it's flat. I've run into several compounds over the years where machining stresses will pull up the cast iron around the bolts. Nothing to do with how Keith did his setup, just saying. I'm sure Kieth did not use gorilla grip when he snugged up the bolts on his mill table. Got to remember, he only taking a few thousandths off, not hogging off .250" in a pass. The other thing I would have done was put a piece of copy paper or news paper under the slide before clamping down. That would keep it from shifting or moving around when machining. He explained why he didn't position the slide in the x-axis direction to machine. I have a similar Index mill that creates flatness issues when machining in the x-axis direction, too. The mill is not the proper machine tool to rebuild slides with, but is the most practical to use. That's why they get used for doing this kind of stuff. We got to remember, we get too critical on how accurate a machine tool machines a slide. That's why back in the days, they scraped and fitted machine slides, to correct the inaccuracy of the machine tool and setup that was used to originally machine the slide in the first place. Hey, it's all good and great input, too. Ken

[@dans_Learning_Curve]

#2

[@chevy6299]

I think you have doubled the value of the lath not that you plan on sell it. Now for a project for the Monarch.

[@petervance9886]

Keith i have an old lathe that had the carige run into the chuck. It has gouges where the chuck hit the casting.Do you know any to fix this?

[@xenonram]

File/grind it flat if any areas were upset above the surface height, then use a die grinder to get the gouges uniform. Then weld/braze it up and dress it flat/even, and finish with paint.

[@jonka1]

I would leave it alone. Certainly don't braze up or weld the blemishes as you risk warping the carriage for no good reason. If you must fix it use filler and paint it.

[@CraigLYoung]

Keith, will you have to add that filler material to the dove tails, please don't ask me to spell it's name?

[@bobrobert6277]

it's turcite.

[@theworkshopmechanicchannel3296]

Bob Robert Exactly 😉

[@bobrobert6277]

also it depend on much he gonna need to remove on the opposite part maybe the gib can fill it

[@ramonching7772]

Is it that easy to grind to within a tenth thousand? Those numbers are already being brag about in modern production machine. Not state of the art. Just brand new normal surface grinder.

[@hotoderschrott5310]

The top surfaces have no contact at all. So they're kind of unimportant but totally stupid polished like a mirror. The angular surfaces that make contact and are critical to guidance are only milled and not ground. Ridiculous.

[@Landrew0]

Maybe it's just me, but I get tired of hearing about scraping.