In article , Harold and Susan Vordos says...

It's taken this many exchanged for the fact that he is using a negative rake
tool, not a positive rake one, to surface. At this point I'm beginning to
question the ability of the instructor. I can't imagine a poorer
combination if I tried-------a chip welded negative rake insert on aluminum.
Changing to a HSS tool, properly ground, one would experience an astonishing
level of improvement.

Oh. I missed that. Though, if he's using coated carbide, he
probably would effective have a negative rake tool even if it were
in a positive holder for tpg inserts.

I agree---the coated inserts are likely a poor choice, but there are no good
choices when it comes to negative rake and aluminum. It screams for
positive rake for good performance. Positive rake, with a proper chip
breaker. There is little to be gained by using negative rake for
aluminum.

Is there *anything* to be gained, ever?

He could have made 100 of those flywheels with a HSS tool ground
with only three grinds, and a proper mandreal and pusher block,
in one day.

Jim


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