Does anyone know what the course 3/8" thread is on the petrol cap wing nut, I've tried a 3/8" Whit nut and it won't touch it and also a 3/8" UNC nut, I'm not sure if the thread on my wing nut has been stretched out of proportion or what the thread angle is, all I do know is that it is standard 16 TPI.
Your help would be greatfully received as I need to re-machine the thread before the old one looses it's locking nut which is already about to fall off.
What I would like to do is machine all the old thread off, drill and ream a 5/16" hole in the bottom of the head on the wingnut and press fit a newly turned stainless steel stud into the brass head. I'll cross drill an 1/8" hole through the tapered shank then countersink both sides of the head and using an 1/8" brass brazing rod to pin the stainless bar in and peen other each end and file the brass in to hide the pin.
Has anyone got any experience of doing the same?
Julian
email (option): 79aust@sky.com
Restored at last, my petrol cap that now has the same arrangement as my oil cap and no longer drops all its bits into the tank when slackened off with the new stainless stud, 1/4" x 26tpi BCT thread on the bottom and 3/8" x 16tpi Whit thread on the top, press fitted into the cap with an 8.5mm hole and an 8.53mm stub diameter, fits beautifully.
It does make me wonder how many of these wing nuts have been thrown away due to the bottom nut snapping off at some point or due to the threads being overstreched like mine was with the brass thread?
Julian
email (option): 79Aust@sky.com