Direct from SRM Engineering in the UK.
Sick of having your cush drive nut come loose?
SRM has the answer! This new cush drive nut is made as BSA should have done in the first place. This nut must be torqued to 65 lbs. This is not possible with a C spanner! But with a hex head, you can now use a torque wrench to get it right!
Also available is a Degree Wheel made specifically for this part.