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As an aside, there's a WWII story--true AFAIK--about Packard building
the (fantastic) Merlin engine under license from RR. The Packard
engineers where aghast to find that the Merlin used over 400 different
fasteners; they re-engineered the engine to use about 100 (or less).
Another tale I heard once was about an American Air Force team doing a
flying exhibition in England with F-86 Sabres. One of the inspection
panels came loose, and one of the ground crew casually walked out,
closed it and fastened a quarter-turn screw with a screwdriver. The Brit
military personnel in attendance were astounded; for their planes, only
a crew chief could tackle such a job, required re-fitting and
re-attaching several pieces of skin, several different fasteners, and a
ream of paperwork.
Bob
On 6/1/2020 8:26 AM, Hap Polk wrote:
>
> 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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As an aside, there's a WWII story--true AFAIK--about Packard
building the (fantastic) Merlin engine under license from RR. The
Packard engineers where aghast to find that the Merlin used over 400
different fasteners; they re-engineered the engine to use about 100
(or less).<br>
<br>
Another tale I heard once was about an American Air Force team doing
a flying exhibition in England with F-86 Sabres. One of the
inspection panels came loose, and one of the ground crew casually
walked out, closed it and fastened a quarter-turn screw with a
screwdriver. The Brit military personnel in attendance were
astounded; for their planes, only a crew chief could tackle such a
job, required re-fitting and re-attaching several pieces of skin,
several different fasteners, and a ream of paperwork.<br>
<br>
Bob<br>
<br>
<div class="moz-cite-prefix">On 6/1/2020 8:26 AM, Hap Polk wrote:<br>
</div>
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<p class="MsoNormal">Curtis,<o:p></o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you again for your authoritative
contribution.<o:p></o:p></p>
<p class="MsoNormal">Hap<o:p></o:p></p>
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<br>
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<br>
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