re: "*Unified Fine (UNF)* - Identical to American SAE Fine and
*Interchangeable*. The angle of the threads is 60 degrees."
Are you sure about this one? For instance, the threads on the large U-bolt that
fastens the axle to rear springs is noted as 'UNF' in, for instance, the Moss
catalog. I believe they are either 5/16" or 3/8." Anyway, we tried to run SAE
fine nuts on them--they'll go about 3/4" inch just fine, then jam. A thread
chaser will go 3/4", then cut, then go 3/4", then cut, etc.
Same story with some of the nuts and bolts on the shock hardware.
bs
--------------------------------
Bob Spidell - San Jose, CA
Bob and Listers,
For those who aren't familiar, *by definition*, Whitworth thread forms are
those where the angle of the threads is 55 degrees versus the 60 degrees of
of most modern threads. Therefore the five Whitworth Thread Forms
include...
*British Standard Whitworth (BSW)* - As mentioned as being used on the
generator bracket and not exclusive to the 100s.
*British Standard Fine (BSF)* - Most engine, transmission & suspension bolts
on 100s.
*British Standard Pipe Parallel (BSP)* *or (BSPP) *- Brass drain plugs and
valves, fuel and brake line fittings on most Healeys.
*British Standard Pipe Tapered (BSPT)* - As above but tapered, not used to
my knowledge on Healeys.
*British Standard Brass (BSB)* - Used in thin walled tubing and ALL have
26TPI no matter the diameter. The mounting post on Lucas SFT/SLT 576
driving lights would have been this thread form.
Other British Fasteners that are *NOT Whitworth* include...
*British Association (BA)* - Used in Healey instruments and fuel pumps. 47
1/2 degree angle of the threads.
*British Standard Cycle (BSC)* - Used on a lot of British motorcycles and
most but NOT ALL threads are 26 TPI. The angle of the threads is 60degrees.
Wikipedia lists BSC as Whitworth and they are WRONG.
*Cycle engineers Institute (CEI)* - Older cycle thread superseded by BSC.
The angle of the threads is 60 degrees.
The following two are what the British switched to after moving from the
Whitworth standard.
*Unified Coarse (UNC)* - Identical to American SAE Coarse and *
Interchangeable*. The angle of the threads is 60 degrees.
*Unified Fine (UNF)* - Identical to American SAE Fine and *Interchangeable*.
The angle of the threads is 60 degrees.
Cheers,
Curt
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