On Sunday, June 24, 2012 2:49:51 PM UTC-4, (unknown) wrote:
The saw is a horizontal band saw using a 3/4 blade. The problem is new
and is not related to blade pitch or to a particular blade. When
sawing 5" diameter aluminum the cut is square for about a third of the
cut and then the cut becomes concave for a little more than a third,
and finally the cut straightens out. The roller saw guides are
adjusted properly and the saw cuts square otherwise. The concavity is
about 1/16 inch. Anybody seen this before?
Thanks,
Eric

It sounds as if the blade gets hot , expands , and loses tension. I wonder if a belleville washer could keep the tension more constant. Coolant might help.

Have you tried stopping the cut and rotating the part so the saw is not cutting a full 5 inches?

Dan