[Tigers] Whitworth Threads

[Marc James Small]

At 11:05 AM 10/15/2009, Carmods at aol.com wrote:
 >Here is some brief  information you all  have wanted to know about
 >Whitworth  threads. You will be amazed at how interesting a topic this
 >will be at
 >your next  party. If you need more detail let me know.

Interesting stuff.  The Whitworth thread remains
the most serious such design due to its
superiority in resistance to unintentional
unthreading.  For that reason, the Royal
Microscope Society made it the international
standard for scientific uses at the Brussels
Convention in 1870.  Whitworth remains the norm
on matters such as microscope objectives and the
like --  macro lenses today still use "the Royal
Screw" as their standard thread-mount, and that is Whitworth, all the way.

When the noted microscope company, E Leitz
Wetzlar, got around to producing an
interchangeable-lens camera, their chief
mechanical designer, Oscar Barnack, selected a
thread of 39mm by 26 turns-per-inch Whitworth.
This caused problems with both FED, a Soviet
concern, before WWII, and Canon, a Japanese
company, after that war, as neither were
microscope companies and thus could not
understand that true Leica thread-mount (LTM) was
not M39 (39mm by 1mm DIN thread).  Both companies finally got it right.

Whitworth rules!

(I do have a few copies of my book on non-Leitz
LTM lenses still available.  Contact me if
interested in buying one.  The Japanese-language
edition, of course, being rarer, costs more than the English-language one.)

Marc


msmall at aya.yale.edu
Cha robh b`s fir gun ghr`s fir!