Yes, and well beaten.
Almost. His big specialty was fuel injection for gasoline engines, largely for airplanes. He made prototype pumps from steel pistons closely fitted into steel cylinders. He showed me one when I was a kid. The piston was about 0.5" diameter, and the stroke was about 2". The fit was tight enough to be almost airtight, and a single stray dust particle caused a screech. I recall him saying that the clearance was
0.0001" or so. I think that this DuMore was in charge of grinding the bores and pistons to final shape.Not so much, I think, because the pulley diameters will be chosen so the belt only rarely comes back to the same place. The effect is to frost the surface and wear it away.
Joe Gwinn