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Looking at getting a 5" 3-jaw chuck for my lathe, 2 piece jaws worth it?

Domodude17

Aluminum
Joined
Aug 14, 2017
The 3 jaw that came with the 9A is in poor shape, so i've exclusively been using the 4 jaw. Getting tired of manually dialing everything, i'm looking into getting a new 3 jaw. As near as I can tell, the recommended size for a 9" lathe is a 5" 3 jaw chuck. Shars has a few in this size, one without 2 piece jaws for ~$80, and one with 2 piece jaws for ~$170.

It seems like the advantages of the 2 piece jaws are that you don't need to take the jaws out to flip them around, don't have to keep track of a 2nd set of jaws, and could make replaceable soft jaws for it. I don't know if I can buy soft jaws or not for the chuck with plain jaws, and it'd definitely be nice to have this capability. Thoughts?
 
I have 3-jaw chucks in both configurations. There are plus and negative aspects for either configuration. With the 2-piece jaw, you don't have to worry about taking jaws out, keeping track of them, and trying to re-sync the jaws with the spiral when you put them back. I find that with the 1 piece jaws--either reversible or with 2 sets--the chuck is less "clunky." The two-piece jaws are big and they will tend to get in the way if you're working up close to the chuck. You may just have to experience both in order to make up your own mind on the topic.
 
Not going to comment on Shars...but - look at the math.
2 x $80 is 160. Which is less than 170. Just swap chucks. I have two 3 jaw chucks, one has outside jaws, the other has inside jaws, and hardly ever gets used in my shop.
OP- you can probably dial your 4 jaw in to the same accuracy you are going to get out of one of those 3 jaws pretty durn quick. They all have run-out. More money, less run-out.
 
I have an old Union 5" 3 Jaw with 2 Pc. Jaws.
I have made several sets of soft jaws for it.
They are used for applications where I can't fit the part into any of my chucks. Such as a tall dish shape on one side of a part etc.
Or very thin parts where the step on the standard jaws are way too big.

Bill
 
I have a 6" 3-jaw and 6" 6-jaw chuck on my 9" SBL. I found it to have much better capacity and a tad better holding power than that of a 5" 3-jaw chuck.
It's funny, I just mounted a 5" 3-jaw chuck on my 14" lathe. I did that to take advantage using the outside jaws to hold thin disks that I couldn't hold using my 8" or 9" 3-jaw chuck.

Sent from my SAMSUNG-SM-G920A using Tapatalk
 
Dialing in a 4-jaw to within 2 or 3 thou (same accuracy as a regular 3-jaw scroll) only takes a minute, I don't see it as a big deal. And, you can dial it in dead-nuts when needed.
 
Decent 3 jaw with an adjust true back would be nice.
2 or 3 thow three jaw would be nice.
I had a lathe chuck on a grinder that would do 1 to 3 thow .. Most lathes 3 jaws were about .005 or worse. ...some way worse
So I did most close work in an independent 4jaw or between centers.
 
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Interesting thread as I am thinking of getting either a 5" or 6" Shars 3 jaw, 2 piece chuck for my 9A. Sorry, I can't afford anything more. But since I have a very nice tight Skinner 4006 6" 4 jaw, I'm thinking to buy the less expensive 5" to replace the 5" Cushman 3 jaw. Aside from being a little less expensive than the 6", I have a cast iron bar bell weight that is just wide enough to turn a back plate that costs me $6.

My question is even though I have a 6" 4 jaw, will I miss the rather significant size capacity of the 6" if I get the 5" 3 jaw 2 piece chuck?
 








 
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