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Ian B
12-08-2005, 09:05 AM
Anyone know what the point of a 2 jaw chuck is? I saw this for sale on Ebay:

http://cgi.ebay.co.uk/2-Jaw-Lathe-Chuck-100mm-with-Soft-Jaws-By-Tos_W0QQitemZ7567886988QQcategoryZ92083QQrdZ1QQcmd ZViewItem

and, unless the idea is always to use soft jaws and bore a hole that closes around a fixed size shaft, I can't see how they'd hold work securely.

Anyone enlighten me?

Thanks,

Ian

ZINOM
12-08-2005, 10:07 AM
Yeah, I believe it is meant to be a soft jaw chuck....and in that case I'd say two jaws would be secure enough for a fair amount of tasks.

Why two jaws over three?....speed in repeated chucking and re-chucking?

John

jstinem
12-08-2005, 10:24 AM
If it's like a drill chuck, meaning no thru hole, then it would be much easier and cheaper to build. Just put the jaws on a single screw with left hand theads on one end and right on the other. It could be done competely by hand if you had to.
Joe

Forrest Addy
12-08-2005, 12:40 PM
A two jaw chuck is a vice that rotates on a spindle. It's intended for soft jaws configured to grip irregular external registration features like pipe fittings, small valve bodies, etc. It's most commonly used on a production machine like a turret lathe, an automatic, or a CNC machine. Thus the portion requiring turning work is presented for machining. Since the part registration is dependent on the jaw config making the jaws is highly skilled work. Once made, the jaws last for months in heavy procuction cranking out tens of thousands of parts.

A two jaw chuck would be a curiosity in a home shop but some used might emerge for one.

[This message has been edited by Forrest Addy (edited 12-08-2005).]

J Tiers
12-08-2005, 12:47 PM
<font face="Verdana, Arial" size="2">Originally posted by jstinem:
If it's like a drill chuck, meaning no thru hole, then it would be much easier and cheaper to build. Just put the jaws on a single screw with left hand theads on one end and right on the other. It could be done competely by hand if you had to.
Joe</font>

Here yah go, 2 jaw drill chuck.......

http://img.photobucket.com/albums/0803/jstanley/CHUCKb.jpg

http://img.photobucket.com/albums/0803/jstanley/CHUCKa.jpg

It came with some other stuff, I assume it is an early type of non-Jacobs drill chuck.

hrhoades
12-08-2005, 04:52 PM
I have one mounted on a hand tapping jig that works well in my home shop.

Timleech
12-08-2005, 06:16 PM
Nothing really to do with the original question, but some drill grinders use a 2-jaw chuck.
I had one which would hold up to 3" dia twist drill, it had 3 pairs of Vee-faced jaws to cover the whole size range

Tim