Clutch lock ring thread size

[marinatlas]

I have been looking about that thread ,and can't find it , accordingto my caliper it is 1 5/8 and 20 TPI , so it seems to be either a special BSC /CEI as the std one is 24 TPI , or a UN -20 (??) , just because I will have to ask to my mate to turn a sleeve and fit it in one gearbox inner cover (after milling it ) , worth a try !

 

[L.A.B.]

There are no Unified threads in the gearbox as far as I'm aware. 20 TPI could also be 55-degree Whit Form.