On the day of Wed, 1 Mar 2006 19:06:18 -0500...
Ned Simmons
typed these letters:


I think it has to do with the fact that the ring with the teeth is not a
perfect fit on the chuck body. Tightening the chuck tends to cock the
ring a bit so it doesn't turn as freely. Moving the key to a different
hole pushes on a different point on the ring and frees it up.

Ned Simmons


Sounds reasonable to me. I've drilled quite a bit of stainless steel
on a Delta 16" drill press were I used to work. At times I was
drilling 1/2 " or larger holes in 1/4" to 1/2" thick stainless flat
stock. Occasionally I would have the bit lock up and the chuck would
keep spinning as the bit broke through the bottom of the steel.
Someone I was working with recommended that I tighten the chuck at all
3 holes. Sounded silly to me at the time but it worked.

Devonshire