Why do the simple jobs go wrong.......

On or around Sun, 29 Jan 2006 19:32:54 +0000 (UTC), "Oily"
<[email protected]> enlightened us thusly:

>
>"Austin Shackles" <[email protected]> wrote in message -
>
><snip>
>
>> >
>> >The mind fair boggles when you remember the "U" stands for "unified".
>> > UNC and UNF (Unified Coarse and Fine), although plenty of threads
>continued to
>> be used such as BS Cycle which used,
>
>Don't forget the plumbers with their B.S.P (pipe) Austin ;-)
>
>Seriously though, I wish they would have stuck with UNC / UNF, especially
>the ones made by GKN, decent quality bolts, not the seemingly metric
>rubbish produced today.

you can get metric bolts made by GKN, of course...

and as to BSP... the BS lot did threads for everything. trouble was, a lot
of foreign people didn't agree

steam engines tend to be whitworth...
--
Austin Shackles. www.ddol-las.net my opinions are just that
Appearances: You don't really need make-up. Celebrate your authentic
face by frightening people in the street.
from the Little Book of Complete B***ocks by Alistair Beaton.

In article <[email protected]>, Austin Shackles
<[email protected]> writes
>steam engines tend to be whitworth...

Isn't it supposed to be the easiest thread form to tap in cast iron?

Regards,

Simonm.

--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, BRISTOL UK www.ukip.org
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SpamTrapSeeSig wrote:

> In article <[email protected]>, Austin Shackles
> <[email protected]> writes
>>steam engines tend to be whitworth...
>
> Isn't it supposed to be the easiest thread form to tap in cast iron?
>
> Regards,
>
> Simonm.
>

Whitworth is better for cast iron simply because it is coarser. What you
have to remember about Whitworth is that he was the first person to
standardise threads. Before him each bolt and nut was hand made to match
and the nut had to be kept with the thread.
The other thing to remember about Whitworth is that the pitches were
designed when the usual material for bolts and nuts was wrought iron (this
is why the nut/head size of Whitworth these days, when steel is usual, is a
size smaller). The ideal thread form and pitch depends on the application
and material, but modern practice is to use the compromise USO metric on
the basis that standardisation is a bigger advantage than fine tuning the
physical advantages.
JD