[TheForge]Slide Rules was Excessive scaling?

[Dann]

Funny, how this thread was so timely for me.

My engineer son and I just had  a conversation about slide rules last 
week.  Following his questions,  I mailed him my dad's good slide 
rule from 1942 era.

I used a slide rule all the way through college, as the electric 
calculators didn't get cheap enough for me until after 
graduation.  Where to put the decimal didn't give me much trouble, 
but I never learned that equation that you posted.  I just forwarded 
that out to my son also.

A Jepsen Flight ( pilot ) calculator is basically a  round slide 
rule.   Mine disappeared sometime during the last 25 years.  When I 
stopped by the FBO / airport for a couple hours of brush up- flight 
time last Spring, I wasn't surprised to see that they are still selling them.

Thanks,
Dann

At 08:29 AM 12/13/2006, you wrote:
>I had an easy trick for getting the decimal place right without 
>doing approximate math.  Graphically I think it was
>
>A | A-1
>---------
>S | S+1
>
>Slide goes left in multiplication, add decimal places - if it goes 
>right, add & subtract one.  Division is shown below the line....
>
>It's been a long time ... I have that drawn on the inside of my case 
>and I would have to look at it to verify but I think I remember it correctly.
>--------
>From: "David E. Smucker" <davesmucker at hotmail.com>
>Date: Tue Dec 12, 3:18 PM
>To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>Subject: Re: [TheForge]Slide Rules was  Excessive scaling?
>
>I had the good fortune to have both my father's K&E from the 30's (BSEE
>1933) and my Post from the 60's (BSME 1968) and gave them both to my son who
>is currently working on his PhD in Computer Science.  Something he can
>display on his office wall.  While I don't have the manual that came with my
>Post, I do have Dad's manual for the K&E.  Nice things to pass on.  I still
>remember my machine design professor who would tell us to bring a bucket of
>water to the final exam to cool or slide rules.  He expected us to be fast
>with our slide rules and to get the damn decimal place in the correct
>spot -- no credit if you miss placed the decimal.
>
>Dave Smucker
>
>----- Original Message -----
>From: "Hufford, David" <David.Hufford at EKU.EDU>
>To: "Sponsored by ABANA" <theforge at mailman.qth.net>
>Sent: Tuesday, December 12, 2006 7:31 AM
>Subject: RE: [TheForge] Excessive scaling?
>
>
>The slide rule ... what an ingenious implement.  I used one all through
>college.  Wish I still had it.  Not long ago I saw one in an 'antique'
>shop, along side an IBM PCJr.
>David Hufford
>Richmond KY
>
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