"Jim Wilkins" wrote in message
...
On Sep 30, 12:42 am, "Michael Koblic" wrote:
"Michael Koblic" wrote in message

...

1) What is the expected stiffness of a drill press spindle? Is bending
arc
of 0.014" to be expected? What would you expect in a mill? Or a lathe?
2) What are the expected tolerances of drill bits? Is 0.010" out of
round
usual?
3) What are the expected tolerances of Jacobs 5/8" chucks? Is
0.010-0.015"
reasonable? I understand that 3-jaw chucks on lathes are not as good at
centering as manually adjusted 4-jaw chucks. Is this about the order of
things?
4) Given that the runout was of the same order throughout the testing
would you say that it is predominantly due to the chuck rather than the
drill bits being out of round?

This seems to be a part of the answer:

http://www.jacobschuck.com/images/pr...20Updated%20(E...

The question is if the runout would be cured by buying a "name" chuck to
replace the existing People's Liberation Army one...At a cost which almost
equals the drill press as a whole.

BTW has anyone tried the hitting-it-with-the hammer adjustment (as
recommended on a couple of forums)?

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

Don't count on drill bits as gages, Jim. They're tapered, as much as 0.003"
toward the butt end. That's true of even the highest quality ones.

Put a mike on a few bits to see.

--
Ed Huntress