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Karl Pearson
 
Posts: n/a
Default Exception (was wood vs metal bandsaw)

Ran across a DoAll saw book at work a number of years ago. As I
remember, the saws were first called Dual (?) meaning regular and high
speed friction sawing.

The book had lots of illustrations and examples. Even directions for
the women who were running the saws in WWII in the aircraft shops.

We had some high speed roller guides (big diameter, ball bearings) and I
tried to set the saw up for high speed cutting (it had 3 speed
ranges), but the boss heard the whine from the high speed and had that
range locked out. We did try friction sawing a couple times, but I
claim that they never got the speed high enough. Wonderful to play
with, though. Would cut high speed steel tool bits!


Ned Simmons wrote:
In article ,
says...

Usual rule of thumb for cutting steel is at least 3 teeth per metal
thickness and speed of 150 to 300 SFPM -- but I've discovered a
notable exception with very thin steel. .



You discovered friction sawing. The purpose made friction
blades are almost all 10 TPI. The teeth soon become rounded
nubs in use, but continue to cut til the weld breaks from
fatigue.

The speed of the saw will limit the thickness of material
to be cut. Real friction saws run at several times the
speed of wood saws, up to 15,000FPM or more. 1/8" stainless
is about the limit on my old DoAll, which tops out at
1500FPM, but I used to regularly cut 1/2" SS on a 36" saw
running at around 6000FPM.

Be careful of sparks, particularly on a saw that's also
used to cut wood or other flammable materials.

More deatils he
http://www.thefabricator.com/xp/Fabr...rticles/Fabric
ating/Article196/Article196_p1.xml

Ned Simmons