--- In STMFC@..., Tony Thompson <thompsonmarytony@s...> wrote:

Pat Wider wrote:

I'm curious, if a modeler just uses them to drill holes in soft
plastic toy
train freight car models at low rpm (to avoid melting the plastic)
with a precision drill
press, why pay extra for high-speed steel drill bits? It's not like
everyone is drilling holes
down into the car's steel weights.  I also have some larger carbide
tipped drills but I
wouldn't use them just to drill brass. No need.

True about plastic, but some of us actually drill brass and stuff,
Pat. The carbon steel dulls a lot faster, whatever it's being drilled
into; softens far easier if overheated (and we've all done it); and is
much more brittle, thus a slight bending by the inattentive or
unskillful drill person is much more likely to break it.
Whatever the reason, I agree with Denny Anspach's estimate of the
carbon steel bit half-life: something less than one project. <vbg>

All true and all dependent upon the material being drilled, whether the drill bit is dry or
has cooling fluid passing over it, the feed rate or pressure being applied, and the drilling
speed being used. Cranking a small carbon steel drill bit with a shaking hand in a pin vise
is just asking for trouble. DUH! I just thought there should be more discussion lest
someone pay extra for something that they didn't need. Carbon steel drill bits do have
their uses. Limited? Perhaps.

Pat Wider