On Thu, 2 Mar 2006 23:51:37 -0800, Harold and Susan Vordos wrote:

"Dave Hinz" wrote in message
...

How can it? The two parts you're exerting force on, are the same parts
in each of the 3 locations.

Simple. Due to inherent clearances of components, the outer member is skewed
by the tightening force, so you benefit by tightening each of the positions,
offsetting the deflection, with a result of a tighter grip. You usually
gain better concentricity in the bargain. If the device was perfect, with
no slop, and no friction, that likely wouldn't be true

Right. Makes perfect sense. I tested it last night on my drillpress
and a fairly tight Jacobs chuck, seemed to behave as expected. If I was
going to engineer something to check the torque at which it spins, well,
then I wouldn't be making stuff. I'm sure someone has done that
already.