I would like to find a rpm chart for cutting steel with a hole saw. Anyone
know of such a creature? For example I have one two inch hole to make in some
plate steel. A slow rpm but how slow? Thanks! Scott

Use a regular drill chart, I would stick down on the low side, maybe
50-60 fpm or 100-120 rpm plus lots of oil or cutting fluid and clean out
the chips often. If the hole saw is HSCO you could probably go up to 200rpm

ShakasCaregiver wrote:

I would like to find a rpm chart for cutting steel with a hole saw. Anyone
know of such a creature? For example I have one two inch hole to make in some
plate steel. A slow rpm but how slow? Thanks! Scott

--
James P Crombie
Slemon Park, PEI
Canada
Machinist - 3D Cad Design - Amateur Astronomer

http://www.jamescrombie.com

Your hole saw has what kind of teeth? If they're tool steel, then use 70 SFM.
A 2" hole has circumference PI*2 or about 6 (roughly). In feet that's about
1/2. So if you run it at 140 rpm you're doing 70 SFM (surface feet/minute).
If the teeth are cemented carbide you can run it about 3 times faster. It
won't hurt to run it slower too. 100 rpm will probably work fine. - GWE

ShakasCaregiver wrote:
I would like to find a rpm chart for cutting steel with a hole saw. Anyone
know of such a creature? For example I have one two inch hole to make in some
plate steel. A slow rpm but how slow? Thanks! Scott

"Grant Erwin" wrote in message
...
Your hole saw has what kind of teeth? If they're tool steel,

Tool steel?

Regards,

Robin

Tool Steel - generic term for hardened steel used in metalworking. The most
common tool steel, by far, is "High Speed Steel" (HSS). HSS as opposed to
ordinary *carbon tool steel* requires more complicated heat treatment.
Ordinary tool steel such as drill rod can be heat treated in the home shop.
HSS cannot - or can't be easily heat treated without the controlled
environment of a high-temp oven. High Speed Steel was "all the rage" in the
metalworking world of 100 years ago.

Bob Swinney



"Robin S." wrote in message
.. .

"Grant Erwin" wrote in message
...
Your hole saw has what kind of teeth? If they're tool steel,

Tool steel?

Regards,

Robin

"Robert Swinney" wrote in message
...
Tool Steel - generic term for hardened steel used in metalworking. The
most
common tool steel, by far, is "High Speed Steel" (HSS). HSS as opposed to
ordinary *carbon tool steel* requires more complicated heat treatment.
Ordinary tool steel such as drill rod can be heat treated in the home
shop.
HSS cannot - or can't be easily heat treated without the controlled
environment of a high-temp oven. High Speed Steel was "all the rage" in
the
metalworking world of 100 years ago.


Yeah yeah yeah, but go and ask a punch/die supplier for a "tool steel" punch
and see if he offers one in HSS. More likely the next question will be "O1
or A2?")

Bimetal hole saws (standard high-quality hole saws like Starrett, Milwaukee,
Lenox, etc.) use HSS teeth and alloy steel bodies.

The bottom line is that while HSS is a "tooling steel" it's not exactly
interchangeable with "tool steel" as far as industry is concerned.

Regards,

Robin

(ShakasCaregiver) wrote in message ...
I would like to find a rpm chart for cutting steel with a hole saw. Anyone
know of such a creature? For example I have one two inch hole to make in some
plate steel. A slow rpm but how slow? Thanks! Scott

Drill a few holes on the waste side of what you are holing for a place
for the chips to go, sawing the chips over and over doesn't contribute
anything.

In article ,
(ShakasCaregiver) wrote:

I would like to find a rpm chart for cutting steel with a hole saw. Anyone
know of such a creature? For example I have one two inch hole to make
in some
plate steel. A slow rpm but how slow? Thanks! Scott

I have just such a chart from a Blu-Mol "The Aggressor" Bi-Metal 3.5" hole
saw. I put it aside when I opened it last week, thinking it might be
useful someday--looks like someday has arrived rather soon. Here are the
recommended RPM settings:

Mild Steel: 95
Tool & Stainless Steel: 45
Cast Iron: 65
Brass: 130
Aluminum: 145
Max RPM: 750

--
Jedd Haas - Artist
http://www.gallerytungsten.com
http://www.epsno.com

Within 8%, the below speeds can be used as suggested SFM for bimetal
hole saws for various materials. In other words, if 95 is the optimal
cutting speed for a 3.5" bimetal hole saw in mild steel, then we think:

SFM = RPM * PI*D/12

And we notice that PI* 3.5/12 = 0.92 which roughly equals 1 (within 8%
like I said). So for 3.5" hole saws only, neglecting the 8% error, the
equation becomes

SFM = RPM

and thus the recommended surface feet per minute for bimetal hole saws
can be inferred directly from the table below. To figure the correct RPM
for a bimetal hole saw of a different diameter in any other material use
the above formula.

Note this is only good for bimetal hole saws. Also, note it won't hurt
much to run a little slower. And yes, lay out your circle and drill a hole
tangent to your circle to allow chips to fall out. A real smart machinist
will drill this hole in the waste material :-)

Grant

Jedd Haas wrote:

I have just such a chart from a Blu-Mol "The Aggressor" Bi-Metal 3.5" hole
saw. I put it aside when I opened it last week, thinking it might be
useful someday--looks like someday has arrived rather soon. Here are the
recommended RPM settings:

Mild Steel: 95
Tool & Stainless Steel: 45
Cast Iron: 65
Brass: 130
Aluminum: 145