Do You Use a 3 Jaw or a 4 Jaw Chuck?

[Janderso]

I have a pretty accurate 3 jaw chuck (Chinese) that came with the lathe , SB 13 single. I bought a 4 jaw Cushman, that is also in great shape. The 3 jaw is so simple to use and I have never mounted the 4 jaw yet.
Just wondering, should I mount the 4 jaw and learn how to use it or continue with the 3 until I have a rectangle or something that I can only use the 4 jaw?
Just wondering what you do.

 

[British Steel]

I rarely use the 3-jaws i have, they only come out when I can make something in one chucking or don't need to worry about concentricity of different features - anything that needs to come out to turn around, for instance, goes in whatever's most suited: 4-jaw, collets or between centres (between centres is the easiest for e.g. shafts that need to be tried for a fit but needs centre drillings in both ends... 4-jaw's essential for eccentric features (cranks, cams etc.), collets for repetitive work small enough to go through the spindle and collet.
A big help when setting up and indicating in the part in a 4-jaw is a second chuck key so you can work on opposing jaws together, makes it a lot quicker! That also implies that you'll need a decent indicator and mount to measure eccentricity, useful (and a nice easy lathe project) is a telescopic "pump centre" when you want to pick up a punch dot on an interesting part to drill / bore / ream - it goes between the tailstock centre and the punch mark and the indicator rides on it, adjust the jaws to centre it, easy peasy!

Dave H. (the other one)

 

[magicniner]

Yes, but mostly an ER40 Collet Chuck!

 

[Chuck K]

Most of my 3 jaw chucks have too much runout to be useful for anything other than a one of part. I have a small 5c 3 jaw chuck that runs just about dead nuts that I like to use for small odd size diameters. 90% of the time I use a 4 jaw. If your 3 jaw has .003 or less of runout I wouldn't have a problem using it for a lot of things. What you don't want to do is avoid using the 4 jaw becauce it's too much work. If you don't take the time to play around with it, it will always be something you avoid. Once you get comfortable with it, it can easily become your go to chuck. There's something to be said for having your material spinning dead true.

 

[benmychree]

On my 19" lathe, I have a 10" 3 jaw buck chuck, can be fine tuned to run dead true, I use it most of the time, also have a 12" 4 jaw and an 8" 4 jaw for square / rectangular work; if work will be ground or removed for fitting, I have a driving plate and dead centers, and a large faceplate for work of that character, and Jacobs rubber flex collets; for the 9" lathe, a new 3 jaw, a nearly new 4 jaw, face and driving plates and collets, both rubber flex and solid type, Bottom line is that perhaps 90% of the time, I use a 3 jaw chuck.

 

[westsailpat]

Getting round stuff to run true in a 4 J is something good to get comfortable with and using your test indicator . For me though just doing general
(round) work I like my 3 J and collet . But say you have to turn a eccentric or you need to hold a block in your lathe or a bunch of other stuff the 4 J is your friend .

 

[Ray C]

Sooner or later, you'll need to hold a square or rectangular piece and a 4 jaw chuck will be needed. There are scroll-type 4 jaw chucks but, you won't be able to hold pieces at offset positions with them.

Which one do I use?... 6 Jaw, 3 Jaw, 4 Jaw and 5C Collet. Whichever one is best suited for the task at hand.

Ray

 

[mikey]

If I'm turning something from raw stock then it doesn't matter if I use a 3 jaw chuck; it will run concentric with the spindle centerline until I take it out of the chuck. It is only when you are doing a second operation on an already turned piece that you have to deal with concentricity issues. In that case, a 4 jaw chuck or a set-tru type chuck is your friend; they can be dialed in to be more accurate than a collet will run, albeit much more tedious to use.

 

[Nogoingback]

I agree with Chuck K. I have a 4 jaw that I use quite a bit and the more I use it, the better I get at setting it up.
I have a Jacobs spindle chuck for parts where runout won't matter.

 

[cathead]

4J