# Crowning a Pulley



## MachineTom (Mar 3, 2011)

In the construction of the Corliss, there are two pulleys with a flat belt that drive the governor. The prints show a crowned profile, although the pulley has guides in the design. The first idea was to just eyeball the profile and file something close. The second idea was to grind a profile cutter, as I had done with a edge and bead radius tool. 

The MHB suggested a crown of 1/20th the width of the belt. In this case that would be about .020", it seemed like alot, the pulleys on my old SB lathes were not near that percentage of crown. Using my TLAR engineering background, 1/40th, 2.5% is what looked about right. The radius dresser would be near its limits to dress a 3" radius on a wheel, but I have a 6" D wheel, so just grind in from the side.

Her is the HSS blank in blocks






On the mag chuck






Grinding finished






Profile cut






Almost completed Pulley






The speed was about 50rpm on the 2" pulley when cutting. The crown is .012" in the .437" width.


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