IME, the shanks of HSS drills are typically soft enough to file without
damaging the file.
If the shanks weren't softer, they would be much more difficult to chuck
without slipping, and likely be a lot more instances of broken drills.

The results would be like chucking an endmill, which will work in some
instances, but is generally a bad practice since most drill chuck jaws
aren't treated with diamond dust for adequate gripping power of hard HSS.

--
WB
..........


"Jim Wilkins" wrote in message
...

For indexing, get a spare chuck that takes a key you already have. A chuck
with a 3/8-24 mounting thread is useful to hold and grind small parts if
you mount it on a long bolt.

Chuck the drill bit in it backwards, insert both keys and clamp the chuck
in your bench vise with both keys resting on the vise jaws. Grind the flat
parallel to the tops of the jaws, the bench leg under the vise, or some
other convenient visual reference line. Repeat with the keys in the other
holes.

I tried this as far as running a file across the bit, parallel to the jaw
tops, but I'm not going to risk damage to a bit or file actually cutting
the three flats.

If you have a belt sander one key should be enough to keep the chuck from
rotating as you hold it on the table to sand in the flats. This light and
compact style of sander substitutes for both a bench grinder and a larger
belt sander for most of my home shop jobs:
http://www.woodworkingtalk.com/attac...5-img_0194.jpg

The platen behind the lower part of the belt lets you grind flat and
square, the unsupported area above is good for rounding off sharp ends and
edges. The version with a disk on the side may be better for woodworkers
but I prefer a larger horizontal belt sander (or a plane) for smoothing
sawn edges.

jsw