On Sun, 8 Jan 1995, Gord Mummery wrote:
> This is a attempt to start a tread on threads.
> [stuff deleted]
> Soooo, of to the local home depot (Its close). I show the sales person in
> the nut department ( really !)." Well", he says," What is that off?" I
> can tell by the look on his face that he will be of no help.
> [more stuff deleted]
> So what exactly is the difference between north american standard and
> british nuts and bolts.
It would have helped if you had told us what make, year, and model car
you're working on, because that makes a difference!
Up to World War II the most commonly used fasteners in British Cars were
British Standard Whitworth (a.k.a. "BSW" or just "Whitworth"), British
Standard Fine ("BSF"), and British Association (BA). BSW was used for
course-thread bolts & nuts, BSW for fine-thread bolts & nuts, and BA for
very small machine screws. BSW and BSF bolt diameters are in inches, but
the thread pitches and thread profiles are very different from US
standard bolts and nuts. BA machine screws are numbered, just like US
standard machine screws, but the diameters, pitches, and profiles are
completely different.
If you need to replace a bolt/nut combination together (and don't care
about originality), you can use a US Standard bolt and nut to replace a
BSW or BSF bolt and nut combination. However, if the bolt goes into a
threaded hole or a nut goes on a stud, then you can't use USS fittings
because a USS nut won't work on a BSW or BSF bolt (or vice versa).
The best source I've found for BSW, BSF, and BA fittings is Metric And
Multistandard Corporation, but I don't have the address handy. The big
BritCar parts places like Moss Motors can usually supply them as well.
Shortly after WW2, most BritCar manufacturers began to convert to the
"Unified" standard, which was for all intents and purposes identical to
our US Standard. Unfortunately, in many transitional cars you'll find a
mixture of British Standard and Unified Standard fittings. Even on cars
which are nominally all Unified, parts supplied by many external
suppliers (Lucas, SU, etc.) still used British standard fittings. Quite
a mess!
To add to the confusion, the engines and transmissions in most Nuffield
Organisation products (Morris, Wolesley, M.G.) made immediately prewar
and postwar (to 1954 or so) used yet another standard, even though the
chassis and bodies used British Standard. Sometimes called "Nuffield
Standard", but more affectionately known as "Nuffield's Mad Metrics",
these bolts and nuts had diameters and threads measured in millimeters,
but used hex heads sized for Whitworth and British Standard wrenches.
It's a long story, so don't ask...
Some time in the 1970's, the UK started converting to the metric system,
so modern BritCars use mostly metrics.
Since your old nuts & bolts don't match anything you can find locally,
and since US Standard and metric _are_ available at virtually any
hardware or auto supply store, you probably have BSW, BSF, and BA
fittings in your car.
> Secondly, does anyone know of any place in the
> west end of Toronto that can supply british nuts and bolts? I whould
> prefer not to have to send off to TRF with the canadian dollar at such a
> sorry state :-(, but that still is an option.
See my earlier comment about Metric & Multistandard Corp, but if your car
is one for which The Roadster Factory supplies parts then you are more
likely to need standard US threads (unless you are working on some part
from SU or Lucas which still used British Standard). Just what _are_ you
working on?
-----------------------------------------------------------------------
Chip Old 1948 M.G. TC TC6710 NEMGTR #2271
Cub Hill, Maryland 1962 Triumph TR4 CT3154LO (daily driver)
fold@mail.bcpl.lib.md.us
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