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From: tomb@hplsla.HP.COM (Tom Bruhns)
Newsgroups: sci.electronics
Subject: Re: A conundrum about the AWG (wire gauge) table
Message-ID: <5170089@hplsla.HP.COM>
Date: 12 Sep 90 00:52:18 GMT
References: <2588@ryn.esg.dec.com>
Organization: HP Lake Stevens, WA
Lines: 25

jeffw@midas.WR.TEK.COM (Jeff Winslow) writes:
>In article <5170088@hplsla.HP.COM> tomb@hplsla.HP.COM (Tom Bruhns) writes:
>>Dunno how it all got started, but you should note that a change of
>>3 in gauge number corresponds exactly to a 2:1 cross-section change.

>Are you sure about that, Tom? According to the tables I have here, it's
>about half a percent off.

>I wouldn't even mention it, except that another poster kept coming up
>with a 1.007 ratio and was wondering why it wasn't exactly 1. I don't know
>the answer either, but it might have something to do with the fact that
>1.007 is just about the ratio of the square root of 10 to pi.

>						Jeff Winslow
>----------

Ooops.  Thanks for pointing it out, Jeff.  That was a rule-of-thumb
I had memorized, and remembered incorrectly as _exact_.  Should have
known better than to post without double-checking it.  Actually it's
interesting that both rules-of-thumb are quite close, certainly
adequate for most applications (and proabaly within the wire-drawing
tolerance, at least over 20 or so gauge numbers...)

Which brings up another question:  What _is_ the tolerance normally
maintained on drawn copper wire?