Decided to put the piston port cylinder back on one of my fleet, had an RT3 top end on but needed the reed block out of it for something else [tough times]. Anyway, the 4--8mm studs were pulled so made up some 9mm [9x1.25 thread], stepped back to 8mm out through the head. Used some waisted bolts out of my honda vigor [blown] car motor. 8mm waised bit was 7.8 but made a good thread & dyed down the 10mm [1.25] end to 9mm. done it before heaps normally using stepped head studs from a TS185 which i had lying around & dye down ok on the 10mm end. The Car bolts were grade 10 & so hard it made my good dye set complain. Lots of oil but thought the neighbours were going to come looking for their cat as sounded like i was standing on its tail. Being 'not' very organised i had the bench grinder on the floor!! giving the threads a good wire brushing after threading--luckily i'd hit the off switch then stood up & the spinning brush pulled me pants down [true], stopped in a rush, jeez. Reminded me of cutting firewood last year behind the Fergy with the 'big' circular saw & took the end out of my glove, too close for comfort that one--getting too complacent [read senile] Cheers.