Three JAW CHUCKs

Lee,

Check my write up in the following thread...my handle is mechman48,

**LINK**=

George.

Before you assume your chuck is 'out', be careful what you check it with. There seemed to be a lot of runout on the chuck on my Boxford and I was all prepared to strip it and put the Hemingway truing mod in. Checked it before disassembly with a PGMS bar. Minimal runout. Most ' round' stock isn't round. Be warned!

Andries

After dismantling, cleaning and re-assembly check for run-out after using only 1 of the 3 chuck tightening points, check all 3 separately and you will most likely find one gives consistently better results than the other 2.

Emgee

The reason - particularly in my case - that subjects/threads get duplicated is that some of us simply do not have the spare time to read everything that is posted here.

Rik

I don't worry about these things unless you need high accuracy for a specific task and ALWAYS use a tailstock centre to keep the job nice and steady

When you want high accuracy, turn between centres

Chuck a bar which sticks a few inches out of a chuck and place a dial indicator touching the back of it

Push it gently with your finger and be amazed at the amount of deflection you see

(Hobby lathes don't do stiffness)

Edited By Ady1 on 16/10/2013 10:39:44

The other system I have used for "fast 3-jaw accuracy" is to turn a fixed centre which fits through the hole of the 3 jaw, plugs into the lathe mandrel and stands just proud of the back of the chuck base

Pin the workpiece centres between this and a good live tailstock, then tighten the chuck jaws onto it

Hello all,

This thread as moved on since I last posted, Pete, had a lot to say, back on page one of the thread, I dont mind though, I did get a couple of tips from his rant!, Anyway I did take the chuck apart, and found lots of small bits of grit in there, I gave it a good clean out allso the scroll was binding, now it moves lots better , and I can actualy see the diference, I did not bother putting a indicator on it, after seeing it is not worth it from peoples post on here, I must get a 4 jaw chuck soon as I can though

Can I say though, regardless of what chuck you have, if you put a Brand new drill press spindle in your lathe chuck teo see if your chuck is running true minimum runout, surely you would need to really concentrate to see it wobble.

All sorted now, I have machined up a few parts that I am happy with.

Thanks everyone

lee