# South Bend 10L Tailstock Problems



## mjonkman (May 31, 2011)

Hi

I bought a South Bend 10L from an ad on Craigslist yesterday. Using wswells.com we dated it to approximately 1946 or so. Its one of the ones with a single change lever on the quick change gear box. Its mounted on the big ole cabinet with the under mounted drive system.

I got it home and in the garage. I figured I'd fire it up - turns out the electrical didn't like the drive home... Rewired the thing today. 

I don't have a headstock center and looks like that will be a very difficult thing to find since it has the proprietary taper. So I couldn't get any idea as to how well the tailstock alignement was. I noticed that something didn't seem right though. When I put a center drill into the a chuck on the tailstock it was way out to the right. At first I thought it was the left - right alignment on the tailstock but after playing a bit (and yes I'll admit not having messed with a tailstock alignment or lathes for pretty much 20+ years I forgot about the alignment marks on the tailstock). Then I realized that the drill chuck that came with the lathe was pretty much a mess, turning it in the tailstock so that the taper turned resulted in the center drill doing a big arc. I figure the arbor must be bent. Got another chuck from and a 1 to 2 adapter (borrowed chuck from my atlas 6"). That seemed better and seemed to approximately align center left to right. Went to drill a center hole right up near the chuck and amazingly I could not get the hole to drill center, it kept drifting to the left. I knew the left and right was close. Then I started looking closer and found that the height of the tailstock looks to be about a 1/16th or maybe even slight more below center. 

The previous owner said he had taken the headstock, tailstock and carriage off to move it a couple of times. That thing is a beast to try and move by oneself. So either there was some shims between the lower and upper parts of the tailstock and they got lost. Or somehow the headstock is on a vertical uphill slope. Because I was so close to the headstock when trying to center drill and there is no noticeable gap between the headstock and bed I'm temporarily going on the assumption of tailstock shims?? 

I have to admit I'm way out of my league on solving this problem. Is it possible that the tailstock had shims - what would a tailstock shim look like? Where would I get them? Without a headstock center, what would I use to get to the right height? I only have a 3-Jaw chuck and a face plate. 

Sincerely
Mark R. Jonkman


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## Tony Wells (May 31, 2011)

Stick a mag base on the face of the chuck and sweep it around the tailstock quill. That will tell you how much and which direction you are off, at that position on the bed. Check it up close, then stretch the indicator out as far as it will reach and slide the tailstock back to that position. Not as good as a test bar, but will get you into a small ballpark.

It's possible that it is not the original tailstock. I have seen that one a couple of lathes, and is usually makes itself known in height.


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## Old Iron (May 31, 2011)

My 13" had some tail stock shims they were just cut from shim stock to fit. I'll be rediong it later.

Paul


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## mjonkman (May 31, 2011)

I did the sweep with the dial indicator. I took a brand new drill chuck arbor and stuck it into the tailstock so that I had a clean surface on which to sweep around on. figure the Jacobs taper on the arbor shouldn't cause too much of a problem since the indicator will always be the same distance out. Using this method I got the left to right offset nearly perfect at 0. But from 0 at the top it is out 60 thousandths by the time I got to the bottom. I still need to retest a few different points, though I'm limited by my mag base and the fact that my dial indicator is too bulky to do a sweep past the carriage.

So I assume that a 30 thousandth shim would bring it approximately into position. 

Interestingly, when aligned this way the witness marks on the end of the tailstock are also visibly offset. To me this indicates that the tailstock may not be the original, or I'm not doing something quite right.

I'm debating whether I should just tear down the whole lathe, clean it up really good and put it back together and then retest and shim as necessary. A visual inspection of the tailstock ways reveals very limited wear - it "looked" uniform from one end to the other. The front way for the saddle definitely shows some wear especially close to the chuck. 

There has to be about 50 coats (okay real exageration) of paint on the thing. Tearing it down and stripping the paint and cleaning all the gunk off of it would be fantastic, of course that involves some serious time. 

I will take some pictures and post them later if I have a chance.


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## mjonkman (May 31, 2011)

I did also validated on the actual shaft of the tailstock - not just the drill chuck arbor. Its just that I can't sweep completely around on the shaft with the keyway in the bottom.


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## mjonkman (May 31, 2011)

Here are some of the images of the lathe

[list type=decimal]
[li]A picture of the lathe and its cabinet[/li]
[li]Bed at the tailstock end showing serial number[/li]
[li]Dial indicator under arbor in tailstock[/li]
[li]Dial indicator on top of arbor in tailstock[/li]
[li]Headstock and gear box[/li]
[li]Gap under tailstock end, about 1/8" between foot casting and the piece directly under the bed[/li]
[li]Tailstock showing misalignment of witness marks after zeroing the left and right offset using dial indicator method[/li]
[li]Closeup of ways with feable attempt to show limited wear on the tailstock way but definite fingernail ridge on inside of front v way[/li]
[/list]


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## Tony Wells (May 31, 2011)

Stick your mag base to the face of the ram, and point your indicator against an unworn part of the bed ways. Crank out the ram and see if it goes uphill or down. Ignore the fluctuations as you crank, those, of course, are just clearance wobbles


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## mjonkman (May 31, 2011)

I've decided that I'm going to strip down the lathe, strip all the paint and clean all the oil and grease and basically rebuilt it as best I can. Then I can set it all up properly levelled and see where things come out at. I'm concerned that there is a gap under the back end of the lathe between the bed and the lathe. Plus the guy I bought it from said he stored it for 8 yrs and he didn't really have a clue as to its operation, I think it best to err on the side of caution and rebuild it and deal with the issues as it comes back together. I doubt the headstock being low is going to fix itself but at least I can eliminate other possible alignment issues. 

Downside is it will take me forever to do it at one night a week.


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## mjonkman (May 31, 2011)

I'll do that tomorrow night.

I did try to leave the indicator tip on the ram of the tailstock while cranking it in and out and it didn't change at all, though in hindsight that didn't do squat since if the tailstock did point up or down it would have never registered that since the indicator was being held in a fixed location.


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## Tony Wells (Jun 1, 2011)

Correct. You need to check parallelism of the ram to the base. Resting the indicator on the ram isn't telling anything useful, really.

Let us know how it goes.


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## mjonkman (Jun 1, 2011)

I struggled a bit with this on - obviously the mag base can't stick to the ram on its own, too heavy for the magnet  So I took a drill chuck and put that into the tailstock and stuck the rod of the mag base into it. Long story short.

Test area: Tailstock back as far as it will go into an area where the frosting is still visible on the ways. Indicator was set as close to vertical as I could eyeball in the flat area between the tailstock vee way and the back saddle vee way. Wiped area clean with cloth before beginning. Initially had a slight problem with the indicator sliding sideways as I moved the ram in and out leading to continous changing values. I took a rubber mallet gave the end of the rod a slight (I do mean slight) rap to seat a little better, tightened up the chuck and the various "knuckles" on the mag base rods. Retried. Set indicator so that it had 220 thousands inset, zeroed it with the dial face, then ran the ram from all the way in (until I felt it starting to tighten up and pusht the chuck out) to all the way out until ram came offf screw. End result was less then half a thousandths in movement and it followed a straight path (as best as I could eyeball). Thus it would appear that the tailstock is most likely flat on the bottom and not tilted forward.


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## Tony Wells (Jun 1, 2011)

That's encouraging news. If, after your clean and rebuild, there is still a vertical alignment issue, a shim would probably be the simplest fix.


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## mjonkman (Jun 2, 2011)

After my original reply I went back and tested as close to the headstock as I could get with the carriage in place and mid way back as well. In both cases the results were identical no movement on the dial indicator (ok. +- 0.0005 - 0.001) but mostly the change was if there was a bit of a ding or piece of dirt along the path of the indicator. Based on the wear (no visible ridge or wear detected by visual inspection) on the tailstock ways it seems that the tailstock may not have been used as much?? I'll probably do a lot more measuring and testing as I start rebuilding the lathe.

Is it okay to start a new thread here and post pictures over time as I do the strip down and rebuild? Or is there a more appropriate forum for that?


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