These belts are suburb for running shop tools, and I find them very
smooth without "once around" thumps that are common with the usual
V-belts.

When the belt on my 1930 Marshall and Wendell Ampico went to shreds, I
replaced it with a Power Twist belt of the appropriate width.  It runs
very smoothly, as expected, but it produces an annoying "buzz" as the
links pass over the pulleys.  I don't think it is appropriate in an
application where silence is the goal.

Larry Emmons