[Healeys] Speedo Drive Thread Size?

[Curtis Arndt]

Listers,

The most common BSC tread used on AHs was the steering wheel shaft thread
and nut.

Also BSC is the early version of, and was superseded by CEI - Cycle
Engineers Institute.

Both BSC and CEI are NOT Whitworth thread forms since they have a 60 degree
thread pitch versus the 55 degree pitch of a Whitworth thread form. The
confusion arises in that fact that the hex heads on either BSC or CEI ( I
can't recall off the top of my head) can be BS/W requiring the appropriate
spanner.

See the attached pdf draft of my article on the subject. Any suggestions
for this article would be greatly appreciated.

Cheers,

Curt Arndt

On Sun, Aug 8, 2021 at 9:27 AM Harold Manifold via Healeys <
healeys at autox.team.net> wrote:

> Just when I thought I had a handle Whitworth, BSPP, BSPT, SAE, UNF, etc.
> along comes BSC (British Standard Cycle). The threads on the transmission
> speedo drive and the angle drive are not the best and could use a
> refreshed. The pitch is 26 TPI and the diameter is ¾” as best I can
> measure. After searching Google the closest match I could find is 3/4" X 26
> TPI BSC.
>
>
>
> I have never heard of British Standard Cycle before. Can anyone confirm if
> this is the tread size?
>
>
>
> Harold
>
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