FRONT RAIL KEYPIN SHAPE

[Newton Hunt]

> I don't think I've ever read why front rail key pins are oval. 

An oval cross section presents a larger bearing surface to reduce
bushing wear.

Turning the pin will reduce this cross section by some small amount
but only after it has been turned 30 degrees or more does the
bearing surface reduce to a point which will cause excessive wear
of the bushing.

Look carefully at an oval sometime to see what I mean.

		Newton