The threaded shaft is made of durable heat treated steel and this unit uses double bearings for strength inside of an anodized aluminum housing. This unit must have a 3/4-16" crank bolt thread to be used.
Can be used on all crank hubs and bearing support hubs that use six 3/8" bolts on a 2.782" bolt circle.
For the BBC fans RCD has put a 1/2-20" thread on the end of the 3/4" stud so the tool can be used for BBC engine applications if chosen. If not going to use the 1/2-20" thread chop it off and the 3/4" thread opportunities will be endless.