Hi, Most PT blade disc bosses have a hole in them, I guess its for that steel bar. Even holding the blade boss still puts strain on that flywheel to crankshaft joint. Its only alloy sort of Dshaped with a flattened area to locate the flywheel. No key way. As I said I damaged one once putting it on. Not sure if the nut was on too loose or what but it put the timing out. Rattle gun is sounding better and better.
Jeff
