Hi, The kick start crank stop on my '31 came with two bolts of an incorrect thread inserted and I ordered two kick start crank stop studs from Walker machine. The studs from Walker's are as follows;

fine thread 5/16" long, unthreaded shank just over 3/16" and coarser threaded portion about 1/2" long.

The threaded holes are too mangled to check the fit by screwing in but depth of the threaded holes in the frame is about 5/16" deep. So on the face of it the short portion of the stud with the finer thread should go in the frame. However I assume it is the coarse thread which should be located in the frame but this may leave the plain bit of the shank too high to bolt down.

So, what am I missing? Which portion of the stud should go in the frame; if it is the coarser thread, is the thread on the stud too long or the hole too shallow or is it just supposed to be like this?

Thanks

Graham

Hi Carl-Eric, thanks for the pointer (I'm not an engineer so apologies if I have this wrong). I look at the R&O but  it shows stop stud part no 24B55 as  1/4 24 so this indicates the thread should be the same both end doesn't it? However I tried the coarse end and it fits the lower chainguard stud hole in the gearbox which according to the manual is 1/4 20/24. I don't have a thread gauge but holding the stud up to a rule and manually counting it looks to me as if he thread is 20 on the long side and 24 on the short side and if the nut is 1/4 24 then the frame end must be 1/4 20 and the frame end must be he coarse end?

I contacted Randy in the end and he replies as follows:

Course thread in frame should be tapped deeper.

Chain guard stud sometimes needs to be ground off if hole is short.

So problem solved but I wonder if the later 1931 frames are different as  the hole is definately not deep enough for the stud. I see from the parts book that the studs were changed to bolts in 1932 and bolts are what were in my frame albeit with mangled threads.