On Sun, Apr 24, 2016 at 10:08 PM, Howard Gibson <hgibson@eol.ca> wrote:
On Sun, 24 Apr 2016 21:07:23 -0500 o1bigtenor <o1bigtenor@gmail.com> wrote:
OK - - - so these are part of the rule changes from the late 50's. Its also when it went from NC and NF to UNC and UNF and there are lots of companies AND people that still use the old designation.
Rule changes this old shouldn't really be a problem for today's use though.
Regards
Dee
o1bigtenor,
I am a mechanical designer, and I have not seen the terms NC and NF in anything other than my French's drafting book from 1941. English screws are UNC, and UNF. The threads on the bottom of your cameras are supposed to be 1/4-20BSW.
There are still lots of machinists, industrial suppliers and individuals that refer to NC and NF threads (National Coarse and National Fine). The thread form is slightly different compared to the UNC and UNF but that too changed in the late 1950's. Just because it doesn't exist doesn't mean that they don't use it - - - grin!! Regards Dee