32A Barrel Studs-Thread size????

[whitehillbillies]

Hi, what is the two thread sizes and length of the 4, 32A barrel studs.
thanks for your time.

whitehillbillies

[340villiers]

Hi, Best to make up your own! The most important thread size is 5/16 BSW going into crankcase. The original studs were/are to short only about 1/2" long into the stud hole. Re-tap the holes with a taper then a bottoming/plug tap, you should achieve about a 3/4"/7/8" in depth! Make up studs to suit, the outside thread can be imp or metric which ever is at hand, use a good quality bar/stud etc.
Finally glue the stud into the c/case again use good quality Loctite,

Best Regards Willie

[whitehillbillies]

Hi Willie, thanks for your prompt reply
the alpha crank that I will replace, has the short rod, the rebuilt bob weight origional one has a quarter inch longer con rod.
The 32A barrel had quarter inch shaved off the bottom to add to a 9E to upgrading it to 250cc, I suspect as I had trouble with piston nipping up. I looked into it and found out the based had'nt been machined, square to the bore. An older retired engineer, squared it up with a home made jig and the problem was solved.
An alloy plate had been made up, to take up the 1/4 inch between the two rods, so the studs were longer, but a year or so ago when restoring my TED20Grey Fergie, I think I used the studs to get the fergie finished, and running,as the threads on the barrel studs were the same.
a 5/16 unc nut runs up the stud so I thought that was the size.
thanks for your time

whitehillbillies

[340villiers]

Hi, 5/16 Whitworth and 5/16 Unc are both 18 tpi. Mix matching may result in the bolt/nut tightening up but you should be ok. Unc is the modern equivalent of BSW/Whitworth, they differ in the thread angle 55 degress opposed to 60.

Regards Willie.

[whitehillbillies]

I was thinking of 5/16 unc the bottom end with 5/16 unf the top.
would this tighten down well enough????
I have got a high tensile 5/16 unf threaded bolt which I was going to cut and add a 5/16 unc the other,with the stud as you sugested lengthened into the crankcase.
thanks for your imput

whitehillbillies