I have a 1930 Sloper with a modified M20 crankshaft. One of the crankpin nut threads has started to strip, possibly because the previous owner used the wrong thread form. It is a 3/4" x 20 tpi nut.
Would this be a 60 deg thread form or a 55 deg thread form?

email (option): pvlietstra@gmail.com

Hi Peter...It is the 20 TPI form of Cycle thread, so the thread angle is 60 degrees...Ian

email (option): ian@wright52.plus.com

hi peter,60 degrees for british standard cycle thread,core diameter 0.696'' thread depth o.026'' hope this helps, cheers rick

email (option): richardholt@rocketmail.com