John,
They were rhetorical questions.
French engineering was done by pastry chefs! ;-)
Prior to WW II most industrialized nations had their own industrial standards including those for fasteners. These standards were developed mostly for mercantile reasons: nonindustrial countries that they exported goods to had to come back to the source for replacement parts.
The US, UK, France, Germany, Italy and Japan all had industries that relied on export business. They all had different standards that were designed for minimal interchangeability.
For example in metric countries, an 8mm diameter bolt could have a hex head size from 12mm to 16mm measured across the flats. The thread pitches were just as varied.
Then there were the Brits with a number of different fastener "standards". Whitworth fasteners were measured across the points of the hex and the sizes marked on "spanners" were the sizes of the bolts not the hex heads.
So let's see, we have the devil's spawn, the much maligned French metric bicycle threads which coincide with ISO industrial standards; then there's the Italian bicycle standard, metric diameters with inch pitch threads given in metric dimensions; and oh yes, let's adopt the obsolete Brit bike standards as the ISO worldwide standard for headsets and bottom brackets!
Blighty still rules the world! ;-)
BTW, in the 1930s Nazi Germany issued an edict that nothing with British threads could be imported into Germany!
Chas. Colerich Oakland, CA USA
John Thompson wrote:
> On 09/04/2009 01:19 PM, verktyg wrote:
>
>> Why would anyone design a system such as this? Why did they use 23.35mm
>> extractor threads!
>>
>> "We are French. We come from France" Beldar Conehead
>
> IIRC, Stronglight invented the square taper cotterless crank. I suspect
> they arbitrarily chose a 16mm bolt to hold it in place, then designed
> the extractor threading around that constraint.