The web of the point of typical twist drills doesn't cut.. instead, it rubs
under pressure to displace the metal (all the way through the workpiece or
to the bottom of a blind hole).
That's exactly what needs to be avoided with work-hardening materials.
Split-point drills begin cutting as soon as contact is made, and continue
cutting until the drill is stopped/withdrawn.
Aside from carbide drills, I believe the best approach would be to use
quality split-point drills, as Phil recommended trying, with a good cutting
lubricant.. while following the "uninterrupted feed" method which is
critical when cutting work-hardening materials, IME.
If the holes need deburred after drilling, a small mounted stone in a
Dremel/rotary tool will be quick, although a larger drill or countersink
will also do the trick (even if just turned with fingers), just so the
turning stops when the pressure is released.
--
WB
..........
"Tim Wescott" wrote in message
...
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.
--
My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?
Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com