Update on various subject

First, take it off the lathe and take it over to the bench. Completely disassemble it. Get the worm out in your hand. Clean it immaculately, and clean in there behind it. Then put it back on, and take out your feeler gages and check the clearance between the center of the worm and the central boss. If there is more than .001" there you have wear which can be taken up by carefully placing one shim so it goes all around the central boss. Finally, clean the jaws immaculately, then reassemble and test. Should get you to .003" or so -- that's what you get with a 3-jaw. There are ways to make any 3-jaw into an "ajust-tru" but it's quite a bit of work. Every 3-jaw needs tearing down every so often for a good cleaning.

GWE

Thanks Grant I thought it might be built up spoog or gungus crud or something, but I really didn't want to tear the thing apart if it didn't need to. Tonight I might see if I can get the thing apart and cleaned.

What would be a good lube when I reassemble the chuck?

Thanks Greg

Here's a post I archived some time ago:

"My choice (for lubricating lathe chucks) is Dow Corning G-N Metal Assembly Paste. It is a light bodied grease loaded with moly, graphite and other solid lubes. A very thin film on the scroll and other friction surfaces makes for a very smooth action that lasts a long time. All chucks eventually have to be taken apart to remove chips, but the thin lube film causes minimal build up."

Sometime I'll get some of that stuff, for now I've just been using lithium grease.

GWE

I got somma that!!! Thank Grant

Greg

Grant's information is good, but before you jump through several hoops, you might want to clarify what you said. I gather that you have only .0005" near the spindle, but a distance from the chuck it's more----the .008"/.009" you mentioned. If that be the case, you could have a sprung chuck, which is very likely on such a small one. Often times a short piece is chucked at the very ends of the jaws, then over tightened. The stress permanently deforms the chuck slides, causing the jaws to grip only at the rear. It's a major source of chatter and runout on long objects.

Check the jaws by inserting something hard and ground----an end mill shank, for example, or a drill blanks if you have them. You want this item deep in the chuck, so the jaws grip at the very back, or inside the chuck body. Snug up the jaws (lightly, don't get down on the wrench), then see if you can insert a feeler gauge between the jaws and the chucked item at the outside end. If you can, the chuck is sprung. It can be salvaged by grinding the jaws, which we can talk about if you find that's the problem.

Harold

FWIW, after getting your chuck clean make up a fixtrue like so:

(Scott Logan's web site) Then use a carbide boring bar to just shave a RCH off each of the jaw ends. Everything ends up square and right on center at that diameter.

Karl

Replace the chuck. Though to be fair..thats about normal for a worn chuck of that vintage.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Is that a metric or Imperial measure?