I just spent a couple of hours making an Ebay Browning two-groove sheave a
bit smaller (4.75" pitch diameter to 4.25" PD) for the HF $99.99 air
compressor pump I bought. Surprise! 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. It reverts
to powder when cut. Anyone need a pound or so of iron (steel?) powder?
Great for experiments with magnets. Glad that's over. Now to clean up the
Myford... and my clothes and me. I'd better not get anywhere near an MRI
before I bathe. I'd get sucked right into the magnet.

--
Bob (Chief Pilot, White Knuckle Airways)