I thought I had a pic of it but I didn't so I had to go take a couple.
The first pick is a side view of the drive wheel with the two grommets in place of the original flat spotted friction drive. The set screw holds the drive wheel to the motor shaft.
The second pic shows the hollow end with the flared part I filed away. The outer rim was held in by the flare only. The hole for the set screw shown here was there in both the outer rim and the shaft. All I did was put a set screw in it after putting in the grommets.