Hi thomas18,

The shaft size is the diameter of the engine shaft you just need a tape measure.

The parts are available from any mower shop just supply these numbers to them or do a google search.

Part Numbers are:
GA Spares.

CHD2850 5/8" shaft Genuine Scott Bonnar Part Number A453835

CHD2851 3/4" shaft Genuine Scott Bonnar Part Number A455531


Regards,
[Linked Image]

Bruce


Please do not PM me asking for support. Post on the forums as it helps all members not just the individual.