sittingduck wrote:
I am using some 3 wing carbide tipped slot cutters in my cnc for tapering
wood. They are almost 2" in diameter and 1/8" thick, made by ELENCO.
The new air spindle I have will go about 50,000 rpm at it's lowest
recommended PSI, I imagine the cutter will go a little slower, expecially
when it's cutting, but I would hate to see a chunk of carbide fly off of that
thing going that fast. I used to run 30,000 rpms without any problems, but I
may have just been lucky so far. Any advice appreciated.


I think you have to contact the manufacturer of the cutter for a
max safe RPM. It is dangerous to guess. Without a heavy guard,
you could be easily killed by a 2" diameter tool spinning at that
speed. I computed 208 FPS at 50,000 RPM.

A guy in the area at an aircraft instrument shop apparently connected
24 V to a 12 V gyro instrument, and it exploded and killed him.
I suspect that instrument gyro was no bigger than your cutters, and
likely never got to 50,000 RPM before it burst.

Jon

In article rs.com,
Jon Elson wrote:

sittingduck wrote:
I am using some 3 wing carbide tipped slot cutters in my cnc for tapering
wood. They are almost 2" in diameter and 1/8" thick, made by ELENCO.
The new air spindle I have will go about 50,000 rpm at it's lowest
recommended PSI, I imagine the cutter will go a little slower, expecially
when it's cutting, but I would hate to see a chunk of carbide fly off of
that
thing going that fast. I used to run 30,000 rpms without any problems, but
I
may have just been lucky so far. Any advice appreciated.


I think you have to contact the manufacturer of the cutter for a
max safe RPM. It is dangerous to guess. Without a heavy guard,
you could be easily killed by a 2" diameter tool spinning at that
speed. I computed 208 FPS at 50,000 RPM.

A guy in the area at an aircraft instrument shop apparently connected
24 V to a 12 V gyro instrument, and it exploded and killed him.
I suspect that instrument gyro was no bigger than your cutters, and
likely never got to 50,000 RPM before it burst.

Jon

208 feet per second is a little over 141 miles per hour...

Erik

Subject: Max RMP for slotting cutter
From: Jon Elson
Date: 12/mm/04 07:39 GMT Daylight Time
Message-id: rs.com

sittingduck wrote:
I am using some 3 wing carbide tipped slot cutters in my cnc for tapering
wood. They are almost 2" in diameter and 1/8" thick, made by ELENCO.
The new air spindle I have will go about 50,000 rpm at it's lowest
recommended PSI, I imagine the cutter will go a little slower, expecially
when it's cutting, but I would hate to see a chunk of carbide fly off of
that
thing going that fast. I used to run 30,000 rpms without any problems, but
I
may have just been lucky so far. Any advice appreciated.


I think you have to contact the manufacturer of the cutter for a
max safe RPM. It is dangerous to guess. Without a heavy guard,
you could be easily killed by a 2" diameter tool spinning at that
speed. I computed 208 FPS at 50,000 RPM.

436 FPS, 297 mph
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)

On 12 Sep 2004 08:25:50 GMT, oEmails (Dave Baker)
wrote:

Subject: Max RMP for slotting cutter
From: Jon Elson
Date: 12/mm/04 07:39 GMT Daylight Time
Message-id: rs.com

sittingduck wrote:
I am using some 3 wing carbide tipped slot cutters in my cnc for tapering
wood. They are almost 2" in diameter and 1/8" thick, made by ELENCO.
The new air spindle I have will go about 50,000 rpm at it's lowest
recommended PSI, I imagine the cutter will go a little slower, expecially
when it's cutting, but I would hate to see a chunk of carbide fly off of
that
thing going that fast. I used to run 30,000 rpms without any problems, but
I
may have just been lucky so far. Any advice appreciated.


I think you have to contact the manufacturer of the cutter for a
max safe RPM. It is dangerous to guess. Without a heavy guard,
you could be easily killed by a 2" diameter tool spinning at that
speed. I computed 208 FPS at 50,000 RPM.

436 FPS, 297 mph

Which is right at the low end of target pistol bullet velocities, or
midrange to most pellet guns. While not USUALLY fatal..there are
enough cases to show that fatalities DO occur at that velocity..and if
the pieces are massy or sharp...can screw up your entire day..and may
take your life.

A friends 11 yr old boy managed to shoot himself in the eye with a BB
traveling slower than that directly from the muzzle of the bb gun. The
BB traversed the entire length of his brain, rebounded back from the
anterior rear of the skull and traversed the other half of his brain
stopping just behind his eye ball. He died a vegetable about 5 days
later.

Gunner


Gunner

"At the core of liberalism is the spoiled child -
miserable, as all spoiled children are, unsatisfied,
demanding, ill-disciplined, despotic and useless.
Liberalism is a philosphy of sniveling brats." -- P.J. O'Rourke

"sittingduck" wrote in message
. 1.4...
I am using some 3 wing carbide tipped slot cutters in my cnc for tapering
wood. They are almost 2" in diameter and 1/8" thick, made by ELENCO.
The new air spindle I have will go about 50,000 rpm at it's lowest
recommended PSI, I imagine the cutter will go a little slower, expecially
when it's cutting, but I would hate to see a chunk of carbide fly off of
that
thing going that fast. I used to run 30,000 rpms without any problems, but
I
may have just been lucky so far. Any advice appreciated.


Hiya, Duck.

Can you use a smaller dia tool ???

A heavy or larger diameter tool will likely play havoc on the spindle
bearings given even the slightest imbalance anyways, and the further out
from centerline the imbalance is, the worser it will be on the bearings.

--

SVL