"Amused" wrote in message
...
snip-------

Several years ago, I watched a pole barn being built. The crew used high
speed steel blades, REVERSED in the skill saws to cut the metal.

That process is known as friction sawing, and is used to great advantage for
sawing even heat treated items. DoAll makes vertical band saws
specifically for that application, with blade speeds that exceed 10,000 FPM.
One can saw with a blade inserted with the teeth running backwards equally
as well as with the teeth running forward. They don't cut by the same
principle as low speed machining.

Harold