On Thu, 30 Aug 2012 19:59:34 -0500, Tim Wescott
wrote:

I may have asked this before, but I'm slow:

I have some 304 sheet. I use it to make control-line model airplane
handles. Each handle needs to have about 20 1/16" or .050" holes drilled
in it, in a pair of tidy lines.

This stuff breaks my regular old HSS drill bits, and my drill hand-
sharpening mojo is pretty spotty at 1/16".

I'm using them in a drill press. The whole process feels weird -- it
feels like there's a skin on the metal which prevents the drill from
starting to cut unless I feed it fairly hard, but once broken through
doesn't cause much problem. Most of the time that I break a drill bit
it's because I'm feeding it "just a bit harder", then SPING -- I've
broken another bit.

Is there a better drill bit to use, or have I just doomed myself to
trouble? Is there a better flavor of _stainless_ to use? I understand
that 304 is difficult to work with, but it's what McMaster had in the
thickness I wanted; having experienced its joys, however, I'm ready to
consider something else.

I think my next step is to get a dozen 1/16" drill bits, but if there's
some magic material that'll help here, I'm listening.

If you can live with 1/8" thick material, McMaster has 303 SS up to 2"
wide. Thin 304 sheet is cold rolled, and consequently work hardened,
making it much nastier to machine than hot rolled stock. 303 is a free
machining (relatively speaking) grade, and would be the best bet if
you can use an available size. But not recommended for welding.

--
Ned Simmons