Bulloney. For some reason my email isn't going through even though it wasn't a
forward, reply, etc. but a new message. Consequently, I'm sending it from
webmail this time.
Subject: Re: Nuts and Grease Gun
Date: Thu, 24 Feb 2005 10:57:40 -0800
To: mgs <firstname.lastname@example.org>
> BSF is not the same as SAE fine. At one time MG used a British thread
> designation Unified National. Unified National is very close to
> American National. The only slight difference is the shape of the
> crests and roots of the threads. Look at page H.16 of a TD series shop
> manual. The TD used Unified National threads on later rear axles.
> BSF standards for British Standard Fine. It's thread pitch is different
> than American Natinal Fine.
> Thread Pitch (Threads/inch)
> Nominal Diameter UNC/ANF UNF/ANF BSW BSF
> 1/4 20 28 20 26
> 5/16 18 24 18 22
> 3/8 16 24 16 20
> 7/16 14 20 14 18
> 1/2 13 20 12 16
> 9/16 12 18 12 16
> Thus the BSW (British Standard Whitworth, a course thread) matches the
> thread pitch for the most part of Unified Course (or Amercan National
> Course) in all sizes except 1/2 inch. However I think there may be a
> difference in the thread angles. I would have to do some more checking
> on that.
> But BSF IS NOT the same as Unified National Fine in thread pitch. See
> the chart above.