What is knife edging?

"Knife edging" is the practice of "sharpening" the motor crankshaft so it is no longer round. The major benefit to this technique is reduced rotational mass. Also, the edges are said by some to reduce the resistance of the crankshaft as it is dipped into the oil in the bottom of the engine.

Knife edging is an esoteric technique and is not usually done unless a complete engine rebuilt is already intended.

The jury is still out on the benefits.