"new" To Me South Bend Lathe- Play In Carriage?

C

Cabel

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So a little about me first - I was trained as a basic machinist/welder by the USAF, but that was 30 years ago, and I did a lot more welding than machinist work, but got the bug in my ear to someday get my own machine tools. Now I'm financially able to get back into it to support my other hobby which is restoring and modifying old British sports cars, so I bought a South Bend 9A from a friend of my fathers as a "starter lathe".

One of the first jobs I gave it was to machine a few small parts for adapting a new tool post to the cross slide. While boring out the post hole in the collar (I did not have a drill bit the correct size) I noticed the carriage seemed to be "chattering" and moving up and down enough to be quite visible. The bed seems to be OK (I tightened down the lock near the chuck, then moved the carriage all the way to the tailstock without any binding) but maybe this just means the entire bed is worn? Anyway, I'm looking for:

1) What's the best "guide" on how to service/maintain and restore your South Bend 9A?
2) Where can I get parts at the best prices?

Thanks for any advice you can give this "noobie"
 
Your description of chatter sounds normal for a 9" SBL if boring a large hole, taking too much cut at a time.
May also have something to do with how your cutter is ground, not enough side clearance causing the cutting tool to jump around to cut.
If all of this is ruled out, them you may have some wear in the lathe itself. But you kind of rule that out by snugging the carriage lock and moving the carriage from the chuck to the tailstock end of the bed without it binding.
How about posting some pictures of the bed ways and carriage, and the setup you used to bore with?
 
If you get into that spot again try locking the carriage to the ways and using the top-slide to feed the boring tool. If it still "chatters" then maybe the slack is in the top-slide or cross-slide ways, not at the carriage.

Grab parts and wiggle them by hand, can you see/feel any slack?
Also check the recessed bolts to tighten the top-slide and cross-slide dovetails gibs.

See post #12 here:
http://www.hobby-machinist.com/threads/sb-gibs-coming-loose-why.37608/#post-321976
for pictures of the adjustable gibs on my 1937 SouthBend 9".

-brino
 
an entire bed worn evenly is as good as a brandnew one
but these don exist...
 
it could be back lash. in boring you want the compound's last move to be pulling towards you. same for the cross feed. also check the gibes on the carriage and compound. check your cutter height to low will cause rubbing and chatter.
 
bob308 said:
it could be back lash. in boring you want the compound's last move to be pulling towards you. same for the cross feed. also check the gibes on the carriage and compound. check your cutter height to low will cause rubbing and chatter.
Click to expand...

I agree, snug all the gibs until it is hard to move then back out the adjustment screws about a 1/4 of a turn. Try moving the cross and compound feeds again. See it that helps.
 
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