"F. George McDuffee" wrote in
message news
On Fri, 16 Jan 2015 09:02:02 -0600, "Paul K. Dickman"
wrote:

snip
Llama used an oddball proprietary thread on those screws. You will
not find
a box at the ace hdw.

http://www.gunpartscorp.com/Search.h...rew+&man=LLAMA
/snip

Any one know their rationale for doing so?


--
Unka' George

Before 1947 several countries had their own metric standards:
http://en.wikipedia.org/wiki/Interna...ystem_of_Units

http://www.gewinde-normen.de/en/loewenherz-thread.html

http://www.gewinde-normen.de/en/french-thread.html

http://www.gewinde-normen.de/en/thury-thread.html
"The flank angle is 47.5°."

The standards are a compromise between the need for coarse tapped
threads in weak materials like iron and aluminum castings and fine
threads on screws to maximize the root diameter for strength. That's
why we have coarse and fine pitches. Metric standards are in between
and not ideal for either, as you'd learn fixing motorcycles.
-jsw