Reboring the tailstock

[jwmay]

I would try to find a replacement tailstock on ebay before I would try to bore the tailstock.

That's easy enough. I should have a spare before I tried this anyways.

First figure out if the bore or the quill is worn.

I'll do that. I had only assumed it was the bore because I also assumed it was the more easily worn component. Too many assumptions.
Thanks everyone for your inputs. You have all given me things to think about before I do anything.

 

[jwmay]

I get .001" variance over the length of the quill, with the middle portion being .001" under. I get .005" variance of the bore, with the top of the bore being the highest point at +.003" and the bottom -.002".
Not really sure what to do, except I did find a brand new quill and screw made in China on Ebay that's about .020" larger than the bore in my tailstock and 2.5" longer, with a 3MT socket. Hmmm.

 

[Alcap]

Would you be able to modify your tailstock to take advantage of the longer quill ?

 

[mattthemuppet2]

You can bore out and sleeve your tailstock to your existing quill. Or you can bore out your tailstock and make a new larger quill. That's a bit more challenging, but not impossible. I have an mt3 ranger you can borrow and you can buy bronze acme nuts of the pitch and handedness to match your screw. The rest is just standard lathe operations

 

[jwmay]

Thanks very much! But the crisis had been averted!
Because of this thread, I took a step back to study the problem a little better. Long story short: I machined a new anti rotation pin. I retapped the anti rotation pin threaded hole. After installing the new pin, I mounted an indicator on the saddle, extended the quill as far as it would go, and ran the carriage back and forth. All is right with the world. Evidently the anti rotation pin wasn't properly installed. I center drilled a piece of stock, and it was solid as ever. Actually it was more solid than I've ever experienced on an Atlas lathe.
So unless somebody sees something wrong with my test, I think the problem is solved.