# Society of Robots - Robot Forum

## General Misc => Misc => Topic started by: airman00 on December 17, 2007, 02:49:31 PM

Title: #4 screw
Post by: airman00 on December 17, 2007, 02:49:31 PM
I need to make a hole on a CAD

What size diameter does a #4 machine screw go through?   Would 3/8" be good?

P.S. I cannot test it out tonight and so I need an answer today
Title: Re: #4 screw
Post by: JonHylands on December 17, 2007, 03:06:40 PM
A #4-40 machine screw goes through a 1/8" hole without touching the sides. 7/64 makes a much tighter fit, but hard to slide in and out. I usually drill my #4-40 clearance holes to 1/8".

If you want to drill a hole to tap for #4-40, you need to drill a hole using a #43 drill bit, which is roughly 0.089".

- Jon
Title: Re: #4 screw
Post by: SomeSaba on December 17, 2007, 04:23:50 PM
does anyone have a site that has a chart for all these?

They come in handy.. and i can never find them online
Title: Re: #4 screw
Post by: JonHylands on December 17, 2007, 05:03:57 PM
http://www.americanfastener.com/technical/tap_and_drill_size_chart.asp

- Jon
Title: Re: #4 screw
Post by: airman00 on December 17, 2007, 06:36:29 PM
Thanks guys,
i got this equation to convert # into inches

Diameter = ( # x .013") + .06"
So a #4 screw would be .58" in diameter

Title: Re: #4 screw
Post by: JonHylands on December 17, 2007, 06:58:30 PM

(4 * 0.013") + 0.06" = 0.112"

- Jon
Title: Re: #4 screw
Post by: airman00 on December 17, 2007, 08:02:52 PM

(4 * 0.013") + 0.06" = 0.112"

- Jon

lol  , i realized that !  ;D  I was about to go back and correct the post, since I realized a .58" diameter screw is pretty thick, way too think for a #4/

anyway I used a 5/32" bit
Title: Re: #4 screw
Post by: JonHylands on December 17, 2007, 08:32:05 PM
5/32" will be way too big - your screw will wobble like crazy.

5/32" = 0.156"

I typically use 1/8", which is 0.125"...

- Jon
Title: Re: #4 screw
Post by: airman00 on December 17, 2007, 08:36:00 PM
thanks jon    ;D

1/8 it is !   ;)

i think i'm going to go to sleep now, i had no sleep in the past 24 hours