8-40 screw specs in .000"

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18 October 2006, 14:42

Woodjack

8-40 screw specs in .000"

Does someone know the specs for an 8-40 screw in .000"?
ie; head dia. and thread dia.

thanks in advance.
WJ

18 October 2006, 16:29

malm

The head diameter will vary depending on the screw. I have some here that are .234. The thread diameter is .164

18 October 2006, 17:43

OMJ

The formula for diameter of Number threads is .013 X Number + .060, this is theoretical so taps and screws will be somewhat off.

0-80 o.d. = .060 and so forth.
Number 8 screw is 8 X 13 + .060 or .164

Where did we ever come up with this system?