[Healeys] British car fasteners

[Hap Polk]

Curtis,

Thank you for putting together such a definitive treatise on the fascinating
history of British threaded fasteners and the industry's conversion to U.S.
standards. The British experience is a precursor to the U.S. slow walking
conversion to ISO standards. Looking at Austin-Healey products, one might
think that the Brits were more accommodating to having a variety of
approaches than their U.S. cousins. Might be a cultural thing.

 

I, we, would like to read a supplemental discussion of the relative merits
of the 55 degree rounded roots and peaks thread design versus the U.S.
standard of 60 degree with 'V' roots and peaks. What I remember from past
discussions regarding the overall performance characteristics of modern
thread designs; including thread stripping, pull out strength, and fatigue
resistance favored Whitworth first, then U.S. standard, with ISO bringing up
the rear. Is that your belief?

 

Will you possibly in a later effort describe the best uses of the various
fasteners depending on the materials being joined, loads and their
direction, vibration, load cycling, etcetera in selecting  fine versus
course thread; bolt shoulder, head, bearing surface and wrenching method,
and the many other criteria that enter into fastener selection.

 

You added to the points to consider when judging a car's concours 'as born'
condition. Thank you. However, would you consider expressing your opinion as
to which specific fastened joints a Healey owner might want to use a more
modern substitute fastener to make  a more reliable daily driver?

 

Thank you again for your authoritative contribution.

Hap

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