BSF

[kayzed1]

i have a couple or four studs to make for a mates dad's old BSA motorcycle side car, they are 7/16 and also a couple of 3/8th BSF threads...could some find person tell me the hole size and bar size i need to do these ..much grassy arse...i can do metric but have forgotten all the stuff my dad and school taught me..
Many thanks..Lyn.

[Joules]

The tapping drill sizes are:

3/8" = 8.3mm
7/16" = 9.7mm

Bar size

3/8" = 9.5mm
7/16" = 11.1mm

Hope that is the info you want Lyn.

[Lew_Merrick_PE]

The attached document is written for 60° V-threaqds (though it ought to be fairly simple to recalculate "factors" for Whitworth threads  --  I have never had a need to do so.  --  Lew

[tom osselton]

I cut down some bolts and just rethreaded them using a 55 degree hhs cutter it worked out fine.

[kayzed1]

Many thanks one and all, i will do the deed tomorrow now.
Lyn.