[Antennas] Screw Size

[Rick Karlquist]

torgersonenator at gmail.com wrote:
> Hi
>      My thanks to all those who answered my previous question on screws.
> Now, I have a second one. After going to a nice website,  I made my
> way through a number of choices of screws for my antenna and then was
> faced with a quandary. I wanted 1/8 inch by half inch. Well, I can
> get the half inch long but the screws come in sizes four through
> twelve. How do I chews a number size of screw that is near an eighth
> inch thick or a little bigger? Right now I really wish I had the
> original screws for the antenna.

Here's how it works:

#0 screw goes in a 2/32" = 1/16" hole
#2 screw goes in a 3/32" hole
#4 screw goes in a 4/32" = 1/8" hole
#6 screw goes in a 5/32" hole
#8 screw goes in a 6/32" = 3/16" hole
#10 screw goes in a 7/32" hole
#12 screw goes in a 8/32" = 1/4" hole

The 100% thread diameter of the screw is about 90% of the
size of the hole, allowing for reasonable clearance.
Actual screws are somewhat less than 100% thread, adding
a little more clearance.

This rule of thumb has worked well for me for 30 years.

Rick N6RK