It depends on temperature. Please check previous posts in CR4 there were innumerable number of posts and the links given on this subject.
You can also refer ANSI B16.5
__________________
Fantastic ideas for a Fantastic World, I make the illogical logical.They put me in cars,they put me in yer tv.They put me in stereos and those little radios you stick in your ears.They even put me in watches, they have teeny gremlins for your watches