Originally Posted by Lawn Slave
The "shoulder" height on the standard boss is aprox. 1.6mm. and the height on the boss with the drive pulley is aprox 2.4mm.
LS
EDIT!

The "shoulder" height on the standard boss is aprox. 2.4mm. and the height on the boss with the drive pulley is aprox. 4.6mm.
Sorry my stuff-up.
LS