[Spridgets] Thread about Threads Re: Fuel line question

[WeslakeMonza1330 at aol.com]

Good info.  I don't think I'd call BSP Whitworth but I would call BSW
Whitworth, probably because it has Whitworth in the name.

I like the stuff about cycle threads - are the threaded screws on the
indicator shroud cycle threads?

Weslake-Monza 1330


In a message dated 12/09/2011 01:05:19 GMT Daylight Time,
cnaarndt at gmail.com writes:

Spridgetiers

On Sun, Sep 11, 2011 at 4:04 PM, <_WeslakeMonza1330 at aol.com_
(mailto:WeslakeMonza1330 at aol.com) >  wrote:
<I don't  believe BSP threads are the same as Whitworth threads though I've
not  checked.>

With all due respect, here is a short  primer on British thread forms...

For those who aren't familiar, by definition, Whitworth thread forms are
those where the angle of the  threads is 550 versus the 600 of most modern
threads.  Therefore the five  major Whitworth Thread Forms  include...

British Standard Whitworth  (BSW) - On the Bugeyes, at least, you'll find
that the 5/16 X 18TPI bolt  on the lower front generator bracket is this
thread form.  (This is  somewhat interchangeable with UNC or SAE Coarse which
is
also 18 TPI and will  thread into the hole in the front generator bracket.)
British Standard  Fine (BSF) - Most engine, transmission & suspension bolts
on Austin  Healey 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 threads (obscure if not obsolete) that used the Whitworth 550 angle
include, British Standard Conduit (BSCon), Model Engineers (ME), and British
 Standard Copper (BSCopper).
Other British Fasteners that are NOT Whitworth  include...

British Association (BA) - Used in Healey instruments  and fuel pumps.  47
1/20 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 600.
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Cycle  engineers Institute (CEI) - Older cycle thread superseded by BSC.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 600.

The following  two thread forms are what the British switched to after
moving from the Whitworth standard.  These are the majority of the  fasteners
used on Spridgets.

Unified Coarse (UNC) - Identical to  American SAE Coarse and essentially
Interchangeable.  The angle of  the threads is 60  degrees.
Unified Fine (UNF) - Identical to American SAE Fine  and essentially
Interchangeable.  The angle of the threads is  60  degrees.

Cheers,

Curt

On Sun, Sep 11, 2011 at 4:04 PM, <_WeslakeMonza1330 at aol.com_
(mailto:WeslakeMonza1330 at aol.com) >  wrote:



Yes and no or maybe. British cars do have some BSP and BST - British
Standard Taper or is it BSPT?  However, I don't believe BSP threads are  the
same
as Whitworth threads though I've not checked.  I think you'll  find the
early steering rack, which originated on the Morris Minor has  Whitworth
fittings.  Maybe the dampers have Whitworth threads - Peter C  will know,
probably
all this stuff is in a book when it ought to be in my  head but it's
late.......

Weslake-Monza 1330 - Monday and I should be in bed!


In a message dated 11/09/2011 02:35:20 GMT Daylight Time,
_cnaarndt at gmail.com_ (mailto:cnaarndt at gmail.com)  writes:

Most  pipe threads on British cars of this vintage are Whitworth  threads,
British Standard Pipe (Parallel) to be  specific.