From: utzoo!decvax!genrad!mit-eddi!smh
Newsgroups: net.physics
Title: Re: Screwdriver Mystery
Article-I.D.: mit-eddi.111
Posted: Wed Apr 13 07:47:52 1983
Received: Fri Apr 15 01:51:48 1983
References: houxq.360

As the force exerted increases, the tendency of your hand to
move increases.  Any such deviation parallel to the screw slot
could be expected to reduce the mesh between driver and slot.
Clearly, the angle of deviation for *small* hand motions
(the ones of interest) is approximately linearly proportional
to shaft length.