Subject: formula for small drill sizes?

From: [email-masked] (Greg Lewis)
Date: Tue, 16 Nov 1993 02:11:32 GMT

There has been a thread over on rec.models.railroad about small drill
sizes. I seem to recall reading somewhere a formula that would give
you the number for a given drill based on its diameter. Am I right? If
yes, anyone know the formula? I seem to recall it was for #1-60 or
something like that....
___________________________________________________________________
[email-masked]
Photojournalism sequence, Department of Journalism
CSU Fresno, Fresno, CA 93740

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From: [email-masked] (John Morton)
Date: 16 Nov 1993 15:28:41 GMT

In article <[email-masked]>,
>yes, anyone know the formula? I seem to recall it was for #1-60 or

Not likely.  Just read a table of diameters and numbers, and you will
see there is no rhyme or reason to this system :-).

John Morton					University of California
[email-masked]			Mechanical Engineering
{decvax,cbosgd}!ucbvax!euler!jmorton		Machine Shop

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From: [email-masked] (david.beyerl)
Date: Tue, 16 Nov 1993 17:56:43 GMT

> yes, anyone know the formula? I seem to recall it was for #1-60 or

	While I am not aware of a formula to give the number of a drill
based on its diameter, I am aware of a formula to give the nominal OD of
a machine screw.  Starting with a #0 screw at 0.060 diameter, add 0.013
for each number size above 0, ie.

      Screw	Size
	0	0.060
	1	0.073
	2	0.086	
	3	0.099
	4	0.112
	5	0.125

	From this information, one can determine what size drill to use
when drilling the clearance hole for the screw.

						Dave Beyerl

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From: [email-masked] (Greg Lewis)
Date: Wed, 17 Nov 1993 04:04:43 GMT

Ah yes! Memory refreshed. It was a formula for screw sizes! THANKS!