On 2016-09-08, Rob Lawrence wrote:
replying to John Martin, Rob Lawrence wrote:
This. I get around 0.002 runout at full spindle extension on my jet drill
press at the drill bit shank, but the chuck itself wobbles visibly. While this
may not bode well for vibration, it wouldn't serve anything to measure runout
here by the key holes.
I get 0.002 at the spindle, and less than 0.001 at the arbor, which means, in
short that it's fine, or needs a new chuck that isn't made by Jet

The Jet drill chuck may have been a lot better when brand new,
but if you have ever had a drill bit spin in the chuck, it can deform
the jaws a little and increase the runout.

And -- is the arbor a permanent part of your drill press, or is
it a Morse taper arbor which you purchase to fit the drill chuck and the
spindle? I've seen both types, and prefer the latter. You can buy a
higher quality arbor if you need more precision -- assuming that the
socket in the spindle has little enough runout. (And, it does not take
much debris in the socket to make a very good arbor run out. :-)

Personally, I prefer the Albrecht keyless chucks which tend to
be very good when new and to hold up quite well afterwards.

And -- the acceptable runout varies with the size of the drill
bit. A #80 bit (0.0135" diameter) does not like pretty much any runout
that you can measure -- and even more so if it happens to be a solid
carbide bit of that size. :-) (And you can't hold that small a bit in a
1/2" drill chuck -- even one by Albrecht. But they make smaller ones
appropriate for smaller drill presses. I have a 1/8" Albrecht chuck on
my Cameron sensitive drill press.

The biggest problem with that small a bit in the 1/8" Albrecht
chuck is that it is hard to see to keep the bit centered while closing
the chuck -- and at that size, there is little feel. I rotate the
spindle by hand on the pulley on the top and look for wobble.

The one place where a keyless chuck like the Albrecht is *not* a
good idea is when you are using a left-handed bit to drill out a sheared
off screw -- and have a drill press which will run in reverse. (There
are special versions of the Albrecht chucks which have the ability to
lock once closed -- but of course that is not as convenient for common
use.

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