Machining Powdered Metal - ugh!
 

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

Machining Powdered Metal - ugh!
 

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)

Machining Powdered Metal - ugh!
 

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.

Machining Powdered Metal - ugh!
 

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

Machining Powdered Metal - ugh!
 

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

Machining Powdered Metal - ugh!
 

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

Machining Powdered Metal - ugh!
 

On Mon, 12 Dec 2005 22:48:37 -0500, "Bob Chilcoat"
wrote:

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.

Sintered or pressed metals often behave far differntly, even when of
the same material..due to compression when molding and heat treating
effects.

I turned something once that I KNOW was cast iron..and got chips. My
customers turn powderd metal every day..and get fines.

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Machining Powdered Metal - ugh!
 

"Gunner Asch" wrote in message
...
On Mon, 12 Dec 2005 22:48:37 -0500, "Bob Chilcoat"
wrote:

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.

Sintered or pressed metals often behave far differntly, even when of
the same material..due to compression when molding and heat treating
effects.

I turned something once that I KNOW was cast iron..and got chips. My
customers turn powderd metal every day..and get fines.

Iron-based PM usually produces gritty powder. Decent quality cast iron tends
to produce small, partially-formed chips. There is a *lot* of PM in consumer
products these days (even the bevel gears on angle-head grinders), and less
cast iron.

But it varies all over the map. If you get your hands on some infiltrated,
double-pressed, or HIPped PM, it may turn like wrought metal -- although
it's likely to be harder than hell. And some cast irons turn curly chips.
Low-grade CI can turn into powder. We used to keep a bucket of the powdery
turnings from cheap CI for fire extinguisher, to dump onto magnesium fires.

Ordinary, run-of-the-mill, press-and-sinter ferrous PM tends to machine into
powdery stuff. Whether it's hard depends on whether it was chilled or
quenched, or just allowed to cool in air.

--
Ed Huntress

Machining Powdered Metal - ugh!
 

On Mon, 12 Dec 2005 23:57:07 -0500, "Ed Huntress"
wrote:

"Gunner Asch" wrote in message
.. .
On Mon, 12 Dec 2005 22:48:37 -0500, "Bob Chilcoat"
wrote:

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.

Sintered or pressed metals often behave far differntly, even when of
the same material..due to compression when molding and heat treating
effects.

I turned something once that I KNOW was cast iron..and got chips. My
customers turn powderd metal every day..and get fines.

Iron-based PM usually produces gritty powder. Decent quality cast iron tends
to produce small, partially-formed chips. There is a *lot* of PM in consumer
products these days (even the bevel gears on angle-head grinders), and less
cast iron.

But it varies all over the map. If you get your hands on some infiltrated,
double-pressed, or HIPped PM, it may turn like wrought metal -- although
it's likely to be harder than hell. And some cast irons turn curly chips.
Low-grade CI can turn into powder. We used to keep a bucket of the powdery
turnings from cheap CI for fire extinguisher, to dump onto magnesium fires.

Ordinary, run-of-the-mill, press-and-sinter ferrous PM tends to machine into
powdery stuff. Whether it's hard depends on whether it was chilled or
quenched, or just allowed to cool in air.

If anyone in So. Cal is interested..I may be able to get ya a tour of
a metal powder plant in Anaheim

http://www.metalpowder.com/

Ill need some notice though..to let them remember they owe me some
favors..

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner

Machining Powdered Metal - ugh!
 

On Mon, 12 Dec 2005 22:48:37 -0500, "Bob Chilcoat"
wrote:

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.

Yes they've been making the hubs out of powdered metal for a few
years now. I've not seen a pulley made that way yet but just give them
time and they will.

If the powder was dark gray then it was probably cast iron.

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

Machining Powdered Metal - ugh!
 

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

Machining Powdered Metal - ugh!
 

Bob Chilcoat wrote:

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

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