[Healeys] Reamers

[Curt/Nancy Arndt]

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*Cycle engineers Institute (CEI)* - Older cycle thread superseded by BSC.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

On Mon, Nov 30, 2009 at 7:54 AM, Bob <robertlarson at att.net> wrote:

> Five?  Maybe more...
>
> There is BA (British Association) which is more metric than anything and
> doesn't use the 55 degree
> but is a British thread form.
>
> But, I would think, that there is for sure a 6th.   CEI (Cycle Engineers
> Institute) or BSC (British
> Standard Cycle)
>
> Bob
> 55 BN1  and Whitworth equipped Motorcycles.  Triumph, BSA, Norton,
> Matchless, Royal Enfield
>
> Curt/Nancy Arndt wrote:
>
>> Bob,
>>
>> Whitworth in that I beleive they are BSPP (British Standard Pipe
>> Parallel.)
>>
>>
>> Remember there are five different Whitworth thread forms, i.e. BSW, BSF,
>> BSPP, BSPT, and BSB (British Standard Brass.)
>>
>> British Standard Fine is the most common on the 100s, followed by Bripish
>> Standard Pipe Parallel, and a few British standard Whitworth.
>>
>> Cheers,
>>
>> Curt