I may actually never have tried to machine actual cast iron before (except
for drilling and tapping a few holes). I have machined plenty of mild
steel, however. I guess that's a different animal. I'm not sure what this
is, but I'm willing to concede that it's probably cast iron. The Browning
taper-lock hub, OTOH, is almost certainly a powdered metal part. It is
clearly molded with mold parting lines and fine detail. Not sand cast or
what I've ever seen from cast iron. That's what led me to believe the
sheave was PM too. Live and learn.

--
Bob (Chief Pilot, White Knuckle Airways)


"Wayne Cook" wrote in message
...
On Mon, 12 Dec 2005 18:21:52 -0600, Rastus
wrote:

On Mon, 12 Dec 2005 18:32:16 -0500, Bob Chilcoat wrote:

These aren't cast iron any more;
they're apparently some sort of powdered metal. Hard -- high-speed tool
bits just rolled over and died. Fortunately, I had some carbide bits
that
worked fine, but this stuff doesn't produce a nice curly chip.

Cast iron never produces a curly chip. However, you should
be able to cut it with HSS.

Never say never. :-)

Actually there's so many types of cast iron that this statement
isn't true. It depends on the cast iron type and heat treatment. I've
actually produced some pretty good sized curls in really good quality
cast iron. Cheap cast iron on the other hand will usually powder up.

Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm