In <961108093732_1781644728@emout13.mail.aol.com>, JKearman@aol.com wrote:
>In a message dated 96-11-07 21:12:46 EST, cobra@cdc.hp.com (Roland Dudley)
>writes:
>Would someone tell me the difference between a Whitworth socket and an SAE
>socket? So far, every bolt and nut on my MG has fit one of my Craftsman SAE
>sockets, although the steering wheel nut was a loose fit in a 1" socket and
>too large for a 15/16.
>
Whitworth (a real person) developed precision machinery in England
during the 19th century. The systems developed were standardized so
that tools (spanners, taps, dies) could be built consistently. The
Whitworth screw standard (55 degree cutting angle, if you care) was
used broadly in England until the 20s and 30s, when a second system,
BSF (British Standard Fine) was introduced. These used the same heads
as Whitworth (to preserve the old spanners) but were 1/16 thicker in
cross-section for the same head than the original Whitworth hardware.
In other words, a 1/4" Whitworth bolt had the same head as a 5/16" BSF
bolt. This is important because spanner size was determined by the
cross-section and not the head size, so a proper Whitworth wrench
might be labeled "1/4W-5/16 BSF". The head size is based on diameter
across the POINTS, not the flat of the head (as are SAE (US) bolts)
and so your Craftsman wrenches won't fit them, unless you are lucky
enough to have the old production Craftsman Whitworth series.
That being said, I got a set of some kind of "universal" wrenches
(kinda like Metrinch) and they don't fit either. Thought I'd share
that.
MG started using US standard (SAE/Unified) hardware on the MGA, which
is probably why your wrenches fit just fine. BSF hardware was found
on other British cars (e.g., Rover) through the 60's.
A. B. Bonds
|