"Jim Wilkins" wrote in message
...

"Drill bits are probably good to a thousandth. Dowel pins are cheap and
very accurate.

The better Jacobs chucks are worth it on a milling machine, probably
not on a cheap drill press. Twist drills are flexible anyway and
center themselves on the punch mark, so runout in the chuck doesn't
matter all that much.

The one Enco keyless chuck I have is pretty good, too, although it's
on the tailstock of my lathe where I can't quickly measure the runout.
For small holes they are handier than keyed chucks, for larger ones
they have a problem with slipping.

A good chuck isn't really wasted on the drill press, you can move it
to a better machine later."

***I was thinking along the same lines. I have actually found a real Jacobs
chuck in my possession. I think it is this one:

http://www.jacobschuck.com/images/pr...No%20Crops.pdf

Cost less than $20, but the specs are about the same I am getting now. And
it is, of course, smaller. It was just an interesting exercise.

BTW what TIR would you expect on a, say, 3-inch 3-jaw chuck in a lathe? What
sort of improvement do you expect going to 4-jaw chuck? When you are
mounting a chuck, are most of the mounts self-centering (The Advanced
Machine Work says they just screw on to the spindle but that is surely not
the case in every instance)? Can you center the chuck by using the indicator
on the periphery of the chuck or do you need to chuck something demonstrably
round and center on that?

--
Michael Koblic,
Campbell River, BC