Wonderful disertation on the subject.... and No I didn't know all that ...
worst yet I read and understood it..... now about that life....
Keith
----- Original Message -----
From <CNAArndt at aol.com>
To: <healeys@autox.team.net>; <spridgets@autox.team.net>
Cc: <Rmoment@aol.com>; <robertlarson@worldnet.att.net>;
<rader@interworld.net>
Sent: Monday, April 02, 2001 11:13 PM
Subject: Re: help! Whitworth (Long)
>
> Hi All
>
> I was talking with Roger Moment this evening discussing the thread (no pun
> intended) on Whitworth Tread Forms and I thought that I would try and
clarify
> things a bit.
>
> << In a message dated 04/02/2001 12:18:50 AM Mountain Daylight Time,
> rader@interworld.net writes:
>
> << Gary:
> > Can you please give me a definition of the term "whitworth"
> > I am using it as a rally question and I want to have it correct. >>
>
> Robert Larson responded:
>
> >>For the definition of the term Whitworth it might be interesting to add
> that it is a proper name. It came from Sir Joseph Whitworth (1803-1887)
who
> wrote papers on thread form that were published by the Institution of
Civil
> Engineers in England. He has also been credited with the invention of the
> micrometer, an application of precision threads.<<
>
> O.K., so far correct but let me elaborate further. There are four (4)
> distinct Whitworth Thread Forms, British Standard Whitworth (BSW) which
was
> the original coarse thread developed by Sir Joseph Whitworth in 1841 and
used
> on things like locomotives (then) and for threading into Aluminum where a
> coarse thread is less prone to stripping than a fine one (now). Second in
> the series was British Standard Fine (BSF) which was developed in 1908 for
> other engineering applications. The next two (2) Whitworth Thread Forms
are
> British Standard Pipe (BSP) and British Standard Pipe Tapered (BSPT).
What
> makes these all Whitworth Thread Forms is the fact that they all have a 55
> degree thread angle as well as rounded crests and roots. American Threads
> all have 60 degree thread angles and flat crests and roots.
>
> British Association Thread Form (BA) is a metric based form (47 1/2 degree
> thread angle) which was originally developed by the Swiss for very small
> watch and clock screws, and you will sometimes here the type referred to
as
> the "Swiss Small Screw Standard". The British adopted this thread form on
> 1903 and call it the British Association Thread. BA sizes are designated
by
> the numbers 0BA through 16BA, similar to our American machine screws, but
in
> the BA system, the larger numbers designate the smaller screws. You will
> normally find BA fasteners where bolts smaller than 1/4" are required
e.g.,
> in instruments and electrical components.
>
> British Standard Cycle (BSC), also known as Cycle Engineers Institute
(CEI).
> Just as the name implies, this thread form is found on bicycles and
> motorcycles where the fine threads are less prone to vibrating loose.
This
> thread form has a 60 degree thread angle as with the American thread forms
> but with rounded crests and roots as the rest of the British systems. The
> majority of the cycle fasteners are all 26 threads per inch (TPI)
throughout
> all bolt diameters e.g., 1/4 X 26 TPI, 5/16 X 26 TPI, 3/8 X 26 TPI, 7/16 X
26
> TPI, etc. To confuse matters even more, some of the older cycle threads
had
> either 20 or 24 TPI.
>
> By now anyone who has read this far and better yet who understands all of
> this has no life!
>
> Cheers
>
> Curt Arndt
> Carlsbad, CA
> '55 BN1, '60 AN5
///
/// (If they are dupes, this trailer may also catch them.)
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