Chuck options

If you need a really good grip on a part that is too big for a collet, you can make a set of jaws and bore them to a hair over the diameter of your work. Instead of a thin broken line contact that is typical with standard jaws, you'll get a wide solid line contact. Also, freshly bored soft jaws will not be bell mouthed.

I think 2-piece jaws are an indication of better build quality, even if you don't need soft jaws. Also, if there is a single pinion, that's a good sign but I've never seen that on a 3-jaw.

Consider that the jaws for these chucks can be treated as a consumable. I think you can get a 2nd set of jaws for 20-$ or so.
 
I just wish they made a 2 piece 4"/100mm chuck. Make my life a heck of a lot easier. Don't particularly want to hunt out a 5" / 125mm one then buy an adapter to fit the blinkin thing....
 
MrWhoopee said:
The simple solution is to buy a bigger lathe.

We're here to help.
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Quite! However, space constraints limit me at the moment to a 7x. Do plan on a bigger lathe at some point, providing I can either find or make room for one.
 
I hope any readers make a clear distinction between chucks with 2 piece jaws and 2 jaw chucks.
I think 2 jaw chucks have their place in a shop but they are not interchange able with chucks with 3 or more jaws.

Daryl
MN
 
2 piece jaws, yes - love them. I now have a few machines and a variety of chucks (3, 4 & 6 J, one piece or 2 piece jaws), basically it depends on what you are doing as to what is best, regardless either work. I recently bought a 10” 4J, direct mount, in the catalogue it was offered with 2 piece jaws. In practice it is uncommon to have 2 piece jaws on a 4J (with a 4J you can flip the jaws, also it unlikely one would use soft jaws in a 4J chuck) - it took 6 months to get, probably came direct from the Bison factory (with one piece jaws it was stock in Edmonton). It cost dearly, but it works awesome.

I bought it to fix my bad karma (and the axial alignment of the old 4J was off kilter) - when I bought the lathe 40+ years ago I accidentally drilled into one of the chuck jaws (working on an off center piece) - probably one of the first times I had used it, still brand new. Ever since, that “owie” was a reminder to my mistake. Perhaps it saved me from other goof ups. Regardless I‘ve a nice piece of bling to remind me to be careful.

I am a fan of soft jaws for the 3J, can’t see doing that with the 4J - but now I easily could.

So, yes 2 piece jaws are nice - not usually a game changer.
 
2 piece can asist in your quest for perfect run out.
 
durableoreo said:
Also, if there is a single pinion, that's a good sign but I've never seen that on a 3-jaw.
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I have two Buck 3-jaw adjust-tru chucks that have a single pinion. Both are 8" model 4831...older, still made in the U.S.
 
GrifterGuru said:
I just wish they made a 2 piece 4"/100mm chuck. Make my life a heck of a lot easier. Don't particularly want to hunt out a 5" / 125mm one then buy an adapter to fit the blinkin thing....
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It might be possible to make one... Mill off the top of the jaw. They're not very hard. You'll need some grooves and threaded holes but in principle, it would be a fairly easy modification.
 
durableoreo said:
It might be possible to make one... Mill off the top of the jaw. They're not very hard. You'll need some grooves and threaded holes but in principle, it would be a fairly easy modification.
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Nice idea if you have a mill, which I don't at the moment and no access to one either sadly.
 
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