After using my superspeed for a while and then switching back to my old type, I noticed that the old type is a bit rougher. There are a number of reasons that could cause this. I could have an imperceptible "frown" on the blade... Also some of the teeth have been bent back into place, and this could cause some slight unevenness. No matter what the cause, I think a blade shim could be the answer. So, today I made a shim, and it does lift the blade off the teeth like I hoped. I am going to give it a shot today. Has anybody else had any luck with shims?