Chatter so bad it looks like knurl

Good News...Bad News

The Good New:

Found the problem, and fixed it. Cutting great!! Whoo Hoo

I took the headstock off, and started the re install. Actually found 2 problems. Not sure if one or a combo of both caused the problem.

1. As I was taking the head off the bed, I hoped that I would find the bolt below the spindle loose. Nope. Crap! ....plenty tight. The 2 at the gear side tight as well
Got the head upside down on the bench for further inspection. That bolt hole under the spindle is a blind hole. ran the bolt in, & had about .375 of thread showing before the shoulder. Blew it out, chased the thread, bolt ran in to the shoulder
Hmmmm!

2. Bushing in the compound bracket pretty worn. I was able to get a full round of .001 shim stock around the .750 compound shaft.
Temporary fix, but running without issues

Got the rest of the lathe back . Spent a good bit of time to get the bed really level. Than made test cuts
SMOOTH as BUTTER. I cut all the knurlled/chatter out of the previous test pieces

Not sure which was the problem, but my guess is that it was the single bolt below the spindle. While it was plenty tight, the crud in the hole didn't allow the bolt affix the head-stock properly.

Now that my lathe is working, I can make some new bushings for the compound casting, before the steel shim wears out:))


BAD NEWS:Kinda had my eye on a new, sooner than planned, PM 1236....maybe in a few months




Thanks to all of the fine folks here at HM that responded with great suggestions

ed
 
I have been waiting to hear how you solved this problem. Save my info if you buy a gear head lathe and it chatters.
 
Aha! The crud in the blind hole makes a lot sense. I've done a lot of trouble shooting in my day(mainly electronics). It seems that the little things like yours can cause the most hair pulling. I'm glad that you found it. Mark
 
Like George, I was also waiting to hear what you found. The bottomed out bolt would definitely do it, as with only one bolt holding tight on the spindle end I would foresee nothing but trouble.

Glad to hear that you found the problem and that it is working fine now!
 
Good work finding that shortened bolt hole, had the same once in a truck gearbox made in two halves, split length ways. Whoever built it had torqued it up and lock-wired correctly but it really was noisy until the problem was found because the bearing outer races where roating.

Bernard
 
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