fastbike

I've never seen a thread pitch of 1.1mm specified. That equates to an imperial size of 23.1 tpi. Both pitches are nonsensical on any common lathe. However the measured, and machined size, of the many lock rings that I have made to fit into Shimano compatible cassette hubs are 30.5mm (or 1.2") x 24tpi. This makes sense as 24tpi is a common pitch on bikes (old school headsets, BSC [British standard cycle] bottom brackets, old school freehubs, screw on drum brakes, etc). The reason for the non standard diameter is a side effect from the days of freehubs where the locking cog was threaded 1.375" x 24tpi. As that was an external thread, but the cassette required an internal thread, 1.2" diameter was the size that gave enough wall thickness on the hubshell for splines etc, and enough clearance for the axle and bearings on the inside. Regarding homemade lock rings that start to bind after a couple of turns, I suggest that either the lockring has not been made to spec, or the body has damaged threads.