I now have three (3) different metal to metal clutch assemblies.

(a) 3/4 inch engine output shaft with a compression sleeve and locking nut on the outside of the clutch assembly.

(b) 5/8 inch engine output shaft with a compression sleeve and locking nut on the outside of the clutch assembly.

(c) A tapered engine shaft secured with a spring washer and nut inside the clutch assembly (Villiers 2 stroke engine).

It appears to me that Scott Bonnar 33 had three (3) different engine configurations using the metal-to-metal clutch unit?

Malcolm.