Twelve inch disk is what I was looking at. Most of the belts seem to
be 6x48, which at 1725 RPM gives 2500 fpm. I don't really see where
making the belt longer would do anything other than reduce heat a bit
and extend belt life, especially for light to moderate use.

heat is the issue. the longer the belt the less heat buildup so the faster you
can run it. it will last far longer too.
but if you run a smaller belt faster the heat will burn the wood and make the
belt wear far faster.

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