Just posting some information I came across while looking at other aftermarket axles. Where Ames did not provide this valuable information I noticed that this axle from summit does.

Summit Racing Part Number: SPZ-35060

This axle comes with 2 spacers to accommodate multiple axle bearing options. The spacer needs to be installed before the bearing is pressed on: The thin spacer 1/2 in. is used with sealed RW507CR bearings, and the thick spacer .826 in. is used with set 9 bearings.

Also this axle looks in the picture that it would protrude past the drum face for stock wheels to ride on.