Tailstock axis .052 higher than spindle axis...oh boy...

Been working with my new-to-me 1947 South Bend Model B and it appears the tailstock is quite a lot higher (.050 plus or minus a couple thousandths) than the axis of the headstock. Previous owner didn't knw much about this and only tried to use it a couple times in the 10 plus years he owned it...

I centered a cylindrical part in the 4 jaw chuck with a known center point visible and then chuckd up a new dead centerpoint in the tailstock.. Also tried it with a 3 jaw chuck as well as with a drill chuck and a small drill bit in the tailstock...several combos ...same thing.

I know a lot has been written on this subject but am kinda stuck for a good answer. The lathe is a older green model and the tailstock is painted grey. I would assume the tailstock is newer than the lathe and it would be great if it might be as simple as swapping out the tailstock... Everything looks clean...I did remove the headstock when moving the lathe this fall and re-installed it carefully checking the ways to ensure no dirt or residue was on them...Didn't see any shims...Cant see any dirt or matter on the bottom of the tailstock either...

I can post a couple pics later tomorrow as perhaps this will help.

If the tailstock is not original to your lathe that may be the answer/problem! I always assumed headstocks and tailstocks were ground/mated to 1 specific bed

The tailstock casting is actually two pieces, the upper portion and the base. Remove the tailstock from the lathe, remove the clamp, and back off the two setscrews on either side of the tailstock upper portion. Now remove the base, which may take a little coaxing, and check for shims. Also, it's possible that the upper and lower portions are not mated correctly. The fit can be rather tight, and if the tailstock were taken apart at some point, it's possible that the upper portion is not fully seated on the base. Note that tightening the clamp bolt while it's on the lathe SHOULD force the two halves together.

Also, you might find this helpful: TAILSTOCK ALIGNMENT on LOGAN HARDINGE South Bend Lathes Part 2 - YouTube

Paul

.......I did remove the headstock when moving the lathe this fall and re-installed it carefully checking the ways to ensure no dirt or residue was on them...Didn't see any shims...Cant see any dirt or matter on the bottom of the tailstock either...

Lucky guy ! Usually the tailstock is low , points down , and sometimes twisted in relation to spindle axis . Getting one that has enough meat on it to bring it into alignment without shimming is a bonus .
You wrote that you checked beneath the headstock , but did you look between tailstock top and shoe ? Does it clamp flush ? There are lot numbers top and bottom . Do they match ?
Are you making these measurements today in your ice cold detached shop , or before ?

All parts that contact the ways (headstock, tailstock, carriage) were factory scraped to fit. Swapping with a different tailstock may just give you the same issue. Split the tailstock casting from its base. Be sure there are no shims or crud between the two mating surfaces and that the surfaces mate tightly. If everything checks out and there's still an issue then your easiest option is to mill the excess material off of the base between the mating surface of the base and the tailstock casting NOT off of the part that actually contacts the bed. If I remember right these lathes were shipped with the tailstock +.004 or .005 to allow for wear over time.

Before you do any machining, check the vertical and alignments of the TS spindle. This can save you great deal of heartache later on.
Harry

I know it's not likely, and it probably would be obvious if there's an issue. Before you start cutting on the tailstock, you might want to check out the headstock mounting and make sure everything looks kosher with spindle bearings. Maybe a quick check to verify that a chucked test bar is somewhat square to the world and parallel to the ways.