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)

Bob Chilcoat wrote:

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.

Cast iron DOES produce a black, powdery result, and no chips to speak
of.

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.



yup, machining cast iron is a MESSY business. It also is bad for the
machines, the carbide in the "chips" is highly abrasive.

Jon

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.

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

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

On Mon, 12 Dec 2005 20:12:10 -0600, Wayne Cook wrote:


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 is correct. Just because "I" never machined a different type
of cast iron doesn't mean none exists. LOL

Rastus wrote:

Cast iron never produces a curly chip.

CI _can_ produce short curly chips.

However, you should be able to cut it with HSS.

Disregarding the skin which _can_ be hard. Depending on the alloy and
the speed of cooling down (or tempering after casting).


Nick
--
Motor Modelle // Engine Models
http://www.motor-manufaktur.de
DIY-DRO - YADRO - Eigenbau-Digitalanzeige

Bob Chilcoat wrote:

... the HF $99.99 air
compressor pump I bought. ...

Be sure to let us know your experience with this pump. Bob