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Tail Stock Alignment Help

KBenoit1

Aluminum
Joined
Oct 13, 2019
Hi Guys,

I got this replacement tail stock since my machine didnt come with a factory one. Probably should have checked this before i stripped and painted it.

The vertical alignment to the spindle is way off. I was expecting a few thou and would need some shim stock, but this is way more than that. None of the parts of the tail stock look like they are worn or modified/machined to make it sit lower.

Any advice on what to do here ?
 

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I'm no expert on SB's, so perhaps there's better solutions, but if that tailstock is otherwise good (tight fit to spindle, parallel to bed), I'd shim it the .2" or whatever and be done with it.
 
3/32" is quite a lot. What does the droop of the tailstock look like?

It looks like you have an older workshop model C. Compare the dimensions of your lathe to those in this picture:
SB Tooling Dimensions.jpg
 
Take a good look at the head stock to be sure it is not shimmed up, flat and square, set clean on the bed.

Yes now see it is a 32s scale, thought it was 1/16s (the reason for mentioning .200)













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3/32" is quite a lot. What does the droop of the tailstock look like?

It looks like you have an older workshop model C. Compare the dimensions of your lathe to those in this picture:
View attachment 271060

I will get some measurements later tonight. The lathe the tailstock came off of was from the same year.

What should be the distance from the ways to the center on the tail stock ?

Yes i knew that was what you meant..just thought I would add it.
Buck

looks like a decent lathe but missing the half nut.

what do you mean missing half nut ?
 
Could be that the doner lathe was refitted during it's life and they surfaced both the headstock and tailstock down to adjust for wear in the tailstock? Headstocks and tailstocks ideally are paired and fitted together to the same height, whatever it is.

I agree with the others that shimming it up to height is the way to go once you are SURE that the headstock is flat on the ways with no shims or misalignment. I'd chuck a piece of material up and cut it the same diameter as the tailstock quill, then push the tailstock up against it and use a dial indicator to determine exactly how lined up they are.

If it was me, I'd cut a piece or pieces of shim material the same shape as the tailstock base so there's no gap for junk to get in there.
 
Took a look at few things.

First. The head stock does not look like its shimmed. Its sitting on the bed.


Second. I picked up a 6 position bed turret this weekend. I mounted it, but had no tooling with it. Found a endmill that had a center coolant hole that fit the arbor hole in the turret. Lines up perfectly with the head stock. Tells me its the tail stock that is the problem.

Third. Hard to tell but there might be fly cutter marks on the bottom of the tail stock base. It measures ~.800 thick. Can anyone confirm how thick it should be ?
 

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Suggest you slack the two opposed screws on the tailstock upper, and remove the lower portion.
Inspect both halves for signs of machining.

The underside of the lower portion looks pretty much unmolested.
 
Suggest you slack the two opposed screws on the tailstock upper, and remove the lower portion.
Inspect both halves for signs of machining.

The underside of the lower portion looks pretty much unmolested.

Seconded. That's where the shim has to go, so unavoidable.

Or maybe not so "unavoidable"?

How stout and stable is your newly fitted bed turret?

Not a sin to provide a center for one of the holes, use it for turning 'tween centers.

Then you could peddle the one-holer TS instead of messing with it at all.
 
Guys look at the pictures in my last post. I already separated the upper and lower tailstock. The bottom of the base is the only surface that looks like it might have been modified. My base is measuring. 802". Can someone measure thiers and let me know what it should be?
 
Good to be sure your tail is square to the bottom, might indicate the top of the quill on a plate check because if altered in the past the quality of that work is in question.

Good you have a turret (and it proved height) so with a center and a drill chuck in the turret you can run most lathes jobs until you get the tail useful..
You might face a slug then come on with the tail and mark the slug with a tail center's point then with holding a micrometer close eyeball the mark to know within .002 or so know the approximate shim needed. Yes a height gauge would do the same.

You may have a little bed wear so this check/tail target height may not suggest your exact desired tail height, you may wish to be at perfect line up 5 or 10" away from your chuck depending on your most often type of work.

You might make the shim one piece with having a couple dowel holes, or let a few hold down screws position it so get it in the same position if removed.

Q [what do you mean missing half nut ?]
I did not see the thread dial /half nut in the photo.
 
Thank you Karl, Anyone else to confirm this ?

I think I am going to make some shims using the lathe in aluminum for now to bring it to the right height and long term look for a new base that hasnt been modified.
 
I have two bases here (used) and they measure .890ish and .862ish. What would be the height of your upper tailstock piece? Base to bottom of quill. Mine are 3.328 and 3.260. Not all upper parts were made the same.
 
Shimming is not necessarily as straightforward as you might think.
You need to determine if the wear in the base is "even", it usually is not.

The front tends to wear more than the back due to pressure and chips.
You can still end up with a quill that's not parallel to the bed and angled downwards. Check the lower part of the base on a surface plate or other flat surface and indicate the top surface to quantify the wear.
 








 
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