That's a mighty small bit Harold, but in retrospect, I wasn't thinking.
That stuff does work harden easily. And most of my experience is with 302.


"Harold and Susan Vordos" wrote in message
...

"Tom Gardner" wrote in message
. net...
sninp------

Drill press? Way too slow, 1,200 rpm min. drill a few seconds ease-up
let
the coolant flow down dill a few seconds and so on. Sharp, good bits a
must! Learn to sharpen them by hand, the girls think it's cool.

Shame on you, Tom. That speed in stainless is a sure recipe for
failure.
500 RPM could be too fast.

Keep the tool sharp, don't let it idle---and don't run too fast.
Stainless
work hardens quickly----and what you described is exactly that---work
hardened. If you look carefully at your drill, you'll find it's well
worn
at the margins, and is now drilling a tapered hole, or trying to. The
drill, in order to be restored to being useful, will have to be pushed
back
until the margin is not altered. Could be as much as 1/8", depending on
how
long you leaned on the drill. You heard the sound of a drill grabbing and
then slipping fairly rapidly. That's the nature of stainless.

If you have choices, do as Gunner said, use 303. Se is the best to use,
but
S is very acceptable. Each is slightly lower in corrosion resistance, but
the difference in machining is huge. If you can use a 400 series, 416 is
even better. It's heat treatable, and is the best machining of all the
stainless family.

Harold