[JesseK]

This is all great info -- the kids did an offseason drive train design on their own from scratch (sans help), and if they went down the hex-shaft route I was going to buy the team a 1/2" hex broach for Christmas.

How long does it take to broach a hex through a typical aluminum sprocket (5/8" wide)? We have both a 3-ton press and a (decent) manual lathe available.