Believe it or not, Royal Enfield were still using a half inch Villiers thread on their crankshaft nut up until 2008 when they came out with a completely redesigned motor
G'day Norm
I understand what you mean now.
These are now called cycle threads.
I guess because one of villiers' earliest products were the
freewheel clutches used on bikes.
These were high TPI threads because they used thin
nuts as part of the design.
Cycle threads are still used today.
[see interesting story attached].
Cheers-----------------------
Jack
