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How to align tailstock to grind for reconditioning

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Cadillac

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Recently I acquired a Chinese made universal tool and cutter grinder. Machine is brand new and came with a lot of accessories which was why I got it. Finally got around to fully disassemble clean,debur,oil,and reassemble. Then the learning curve of how to setup and use. Which might take a lifetimeo_O
I mounted the centers on the table about 6" apart and tightened. Centers are built just like a typical tailstock. Base is keyed to the table. Slot on top base is slotted for upper tailstock piece which has a corresponding male with adjustment screws on each side to get adjust side to side and a lock screw. Once aligned tighten screw that holds to table should be done. Well my centers height did not align. They are .022 off. Wtf! I'm no expert but I would think they should be exact for precision. Whats baffling is matting surfaces of tailstock are all scrapped. So I decided to blue up the parts and see what they say.
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Holy cow like said I'm no expert but maybe three or four contact points on a 3x4 base?? Top of base where tailstock slides on was barely touching and on the inside edge only barely. So I decided it would go through and make these centers align the best I can. My plan is to surface grind all the matting parts and then scrape as necessary. My main question is how to align the tailstock base to grind the bottom of base. When every surface is curved or uneven. The only way I have come up with is extending the quill on tailstock and take my measurements from there. The problem is that won't tell me if the base is tiled side to side. I planned on having the quill .0002 high when extended for deflection and wear. But I can figure out how to make sure the base is parrallel to the table. When measured each ear of base slides were different height and tilt. So how can I trust the bottom of the tailstock base. I tried putting a gauge block on surface and level with a .0001 gauge mounted to spindle then to the same to other surface and difference was maxing my gauge so I didn't trust that method of aligning.
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So the question is how to check the tilt "side to side" of the base. Not the length of quill I think I've got that. Unless that's wrong too? Any input appreciated thanks.
 

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Cadillac

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One thing that I’ve done so far is grind both bases the same thickness. I did it in multiple flips and used the thinner one as my final measurement. Because they were way off from each other. Like .012 and there was like .009 difference on one of the ears like .009 from each one on same block front to back. It was kind of a challenge to pick a plain to start from. But they are parallel and the same now. I just need to figure out that bottom of the tailstock base
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Richard King 2

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Remove the quill and make a test bar that slides through the casting and extends out about 3 inches on both sides then set that on 2 Vee blocks and block around it like you did. say .001" smaller ( who knows if the bore is the same size) Then grind the bottom side. If your careful measure the side of the bar and then kiss the key or key slot. Then the bottom will be parallel to the bore in both directions.

Then take the lousy scraped side and either scrape or file the spots there so you can set it on your granite and it doesn't rock. You should be able to tap on the opposite side of the crappy side you filed. tap it with a dead blow hammer and the sound should be the same sound a thud sound at all 4 corners. then set that on your grinder and kiss the other side and once it is cleaned up 90% flip it over and kiss the crappy side.

I can send you more info on scraping as I am getting finger cramps typing now. Oh an by the way that is not "scraping" it's camo to fool people into thinking it is scraped. Rich
 

Bob Korves

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I can send you more info on scraping as I am getting finger cramps typing now. Oh an by the way that is not "scraping" it's camo to fool people into thinking it is scraped. Rich
Amen to that! It is nothing but decoration...
 

Cadillac

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Yeah I’ve seen the decorating before. Why the heck wouldn’t they just grind and leave it? Are they just Scraping the raw casting for semi flat and appearance and that’s it.
Can all the surfaces be just ground. These surfaces arnt sliding on each other. I was thinking it might do?? I do know after grinding the bottom pieces they have a nice vacuum when lifting off the surface plate.
 

Bob Korves

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Why the heck wouldn’t they just grind and leave it?
Because people think they NEED scraped surfaces on their machines. Even old South Bend lathes have decorative scraping on them. It was and is expected. So, it is faked. Scraping is a wonderful way to make a highly accurate surface that can hold oil and last a long time. Grinding and milling can make a highly accurate surface, faster. Sliding parts need oil constantly between the surfaces to prevent wear and stick/slip. Scraping is also an excellent way to make precision machines that are much bigger than surface grinders are. Downside of scraping is that it takes considerable time, and trained and skilled workers are required, and there are not many of them today, certainly not enough to turn out precision scraped Chinese hobby machines. ;) Scraping is a really useful skill for the home shop machinist, where speed of completion and making money are not usually the highest priorities. If auto makers precision scraped the surfaces between the cylinder heads and engine blocks (and other fit ups) of our ordinary cars, no one would be able to afford them. Scraping is also a good way to make really critical fits between parts where money is no object (NASA). So, scraping works well for lots of things, but is not best for all purposes. It is another useful tool in the tool box...
 

Richard King 2

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I'm curious how did you check the .022" ? I hope you didn't sweep around the center. I helped a guy learn how to scrape on the other forum I help on. But won't link to it. Now that you have ground the Tailstock (TS) you know it will below centerline Or it should be.

I wish you would also take a photo of the whole machine so we don't have to guess as far as design goes.. You will need to break up the riding surface and relieve the center 40% of those sliding surfaces so it won't rock as it begins to wear. Bob can explain why as he has taken one of my scraping classes. I would bet the bottom of the Headstock (HS) is as crappy. Have you looked at it? To do it right you would basically do the same thing to HS . Inside the better machine factories they scrape the HS last.
 

Cadillac

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Here's a picture of the machine. From what I could tell cleaning all the cosmoline off the fitment of the saddle was nice. The table slides very nice it has a blue plastic material that I can't think of the name right now but it's what people epoxy on to build up a worn surface on a sliding way. Other than NO oiling ports anywhere "which I will add" the fitment is good. The spindle I took apart and glad I did. Their was grit from the casting all on the inside. A pea drop of grease in the bearings. So I completely cleaned everything used some kluber for the spindle bearings and it actually runs like a top. Wiring was a different story. No regulations over there. Grounds were wrapped to a through bolt on chassis just stripped wires wrapped around screw on painted surface. 220 unit with everything ran with what I would use to wire a door bell for my house. So I rewired everything too
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I measured the tail stocks by having them mouted to the table. Then I put a 10" long 3/4" ground rod with centers cut in both ends in between the centers. Mounting a tenths indicator on the spindle I indicated the rod with the table axis. Then I measured the z difference between each side which was .022. Just looking at the centers they were visible off a lot. Taking a indicator on a height gauge on the machine table and checking the quill height was off like .018. Figured the rest was from having the quill extended and it being tilted that much the other .004. It's probably crude and not the right way but that's what made sense to me?
One question about the way you suggested on the tailstock base alignment with the v blocks on the made "quill". Would that tell me if the base was let's say "rolled"? What I mean is the horizontal part of the base could still be let say 2 and 8 not at 3 and 9 with the quill still being aligned to the axis of surface grinder. That would align the quill but not the base right? Or am I missing something?
My guess is the chuck indexing fixture will be in the same shape. It does spin very well and putting the three jaw on it with the mt4 shank surprisingly with a dowel in the chuck it had .0007 runout. I'm sure it's in the same shape as the centers. That will a another project.
I have so many questions on t&c grinders. Like alignment of head to axis, or index fixture to table or "0" degrees? Cutter flutes to chuck for indexing. Like said their is so much to learn with very little resources out there about the subject. Richard I really appreciate the information given I'm all ears on the advice of reconditioning of this t&c grinder. Im well aware of what I've got and I'm not looking for nasa tool room specs here. I just want to start out not behind the ball. Want to be able to grind my tooling and carbide as I wish and be confident it's cutting on all flutes. And when the centers don't align I think I've got a problem that needs some attention. Much appreciated thanks!
 

Bi11Hudson

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#9
I'm about 3/4 asleep, and after looking 3 or 4 times at your tail stock, I'm still not sure of the ability to move said tail stock side to side. Sorry I'm so fuzzy yet. I think my eyes are bone weary tired.

There is, once you've smoothed the base, a way to "balance"(?) the truth of the tailstock to the head stock. It's not the "end-all" solution, but is rather a quick check to be done when setting up a touchy project. Take a piece of shim stock (I use a piece about 1 X 2 inches, 2-1/2X5cm) with head and tail centers run together. The tilt, or offset of the shim stock will show direction of the error. It doesn't need to be precision, a piece of business card stock will do. Basicly the same system as setting center height for a cutting tool. It should be square to the frame, any misalignment of the centers is indicated by tilt of the shim.

A piece of kitchen aluminium foil will serve to bring the tailstock up if it is too low. Simply placed in the "dovetail" on the tailstock to add a fuzz of height. If too thick, a coat of heavy paint may do. But foil is usually thinner than typing paper. Again, not the end-all solution but may well serve ti get the basic alignment done without a test bar.

Then again, I may just be babbling away. Not really knowing what I'm talkingabout.
 
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