Until about 5 years ago I knew of 2 types of chuck. 4-jaw independent and 3-jaw self-centering.
In the last few years I have started to see 6-jaw scroll chucks and 4 jaw versions of the same. It seems to me that the reason that a self-centering chuck has 3 jaws is that that guarantees that all jaws touch, and have equal clamping force. Assuming a perfectly rigid chuck, and an imperfectly circular workpiece a 4-jaw scroll chuck can only ever grip on two jaws, and will rattle a bit on the other pair. 6-jaws seem like they would work at least as well as 3-jaw, but with extra bits. Though I am not100% convinced. The exactly-opposed jaws seem wrong. I did, a few years ago, design (in my head) a 2 x 2 jaw chuck with two sets of two jaws. I don't know if those have ever been made. (it had no through-hole, it was fairly simplistic) -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
