4-Jaw chuck for metal lathe Q

[sleddriver]

I have a small Taig lathe. I ordered a 4-jaw self-centering chuck and a 4-jaw independent chuck and need to return one. The former has aluminum non-stepped jaws that are reversable. The later has steel stepped jaws that are independantly adjustable.

What I'd like is a self-centering 4-jaw chuck with stepped jaws. Sherline makes one but it's nearly $150. Both of these are right at $70.

I borrowed a friends Sherline 3-jaw self-centering chuck with stepped jaws and it worked fine EXCEPT it won't hold square stock, which was a major drawback for stock that I can cut square or even rectangular and wish to turn round. Thus I was limited to round only.

How much of a PITA is it to use an independant jaw chuck? What's the best way to set it up? I can work to 0.001" but it's rare and I don't see myself making crankshafts for steam engines, etc.

I like the stepped jaws because they can grab the inside of metal or pvc pipe, which has been usefull in the past.

What say you?

 

[tom slick]

What you want is a "scroll" chuck. The independent adjustment of the 4 jaws is considered a feature and give you more over centering the part. It is certainly not as easy to use as a 3 jaw scroll chuck but once you learn how to set it up it is not difficult. Once you have your part centered, you loosen 2 jaws to release the part and tighten the same 2 jaws for the next part and everything stays centered.

Safety note: You must check the jaw tightness against the part every time you use it. I know of a guy that missed checking a jaw on a 14" 4 jaw chuck. As the spindle reached 10k rpm it came off and smashed his eye socket and skull.

Those jaws are aluminum so that you can machine them as needed, it's also why they bolt on. Just machine some steps into them.

 

[sleddriver]

scroll = self-centering? I'll have to try each a bit and see what I think. I have some aluminum and corian I can turn.

Fortunately the little Taig won't even come close to 10,000rpm but your warning is acknowledged. The tool I'm most afraid of in my shop is the table saw. Fortunately after nearly 30 years of using it, I can still count to 10.

I'm interested in hearing the best way to machine steps into the aluminum jaws. How would you suggest going about it? Thanks.

 

[tom slick]

Scroll = all jaws tighten at the same time.

Look up how to machine "soft jaws" and you'll find plenty of information.

Have you looked at the website little machine shop for parts?

Another interesting website http://www.deansphotographica.com/machining/projects/projects.html

 

[sleddriver]

Thanks for the reply. I'll check out the links you provided.

 

[Silk]

Guys I know who did fitting and turning apprenticeships say there weren't allowed to use a self centering 3 jaw chuck, they had to set up everything, even round bar stock in a 4 jaw. That way they couldn't take the easy way out and learned to centre anything.

 

[sleddriver]

This guy nails it quickly using a dial indicator. I just might keep the 4-jaw independant one and make myself a holder for the DI.
http://www.youtube.com/watch?v=HSjQfnXuhEE

 

[sleddriver]

I really like the way this guy modified his tool posts: