# Do you know how to use a slide rule?



## FusionWhite (Feb 2, 2007)

My father in law bought a new house and is moving so last weekend my wife and I were helping him pack. In digging through his attic I found an old slide rule. Being and engineer with a taste for history I decided to learn how to use it. Although its pretty tricky at first once you get the hang of it what it can do is simply amazing. Im still working on log's and trig functions but I can whip up mulitplication and division like a mad man on this thing.

Anyone else mess around with a slide rule on a regular basis? Im thinking of taking it into my next meeting where we're working on something and busting it out when someone needs a calculation done. I bet the look on the old engineers faces would be priceless.


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## Slugger926 (Feb 2, 2007)

Yeah. My parents both being math teachers had slide rules. I wouldn't have gotten through 3rd grade math without one. arty-smiley-048:

Then I learned how to multiply later down the road.


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## Road Guy (Feb 2, 2007)

I have my granddads old slide rule (along with leather case &amp; belt loop attachment)

But I have no clue how to use it, it looked very complicated IMO.


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## FusionWhite (Feb 2, 2007)

Road Guy said:


> I have my granddads old slide rule (along with leather case &amp; belt loop attachment)
> But I have no clue how to use it, it looked very complicated IMO.


Thats what I thought the first time I looked at it. For multiplication and division you can ignore most of the scales and its actually pretty easy. I found a website that explains the theory of how a sliderule works and it was extremely interesting.


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## singlespeed (Feb 2, 2007)

I got a Versalog 1460 (a Cadillac of slide rules) for x-mas  I've had a cheesy plastic slide rule for a decade or so.

I can do simple multiplication and division, roots, powers, trig, etc. I haven't learned how to string long calcs together yet.

I like to keep one around so that when the young whippersnappers around the office start giving me crap about how close I am to taking a dirt nap, I can pull it out calculate just how close I am to taking that dirt nap :whipping: Other than the principals of this firm, I'm the oldest in the office and take a lot of good natured ribbing about my age.

Isn't everyone under 40 just a kid? :dunno:


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## jfusilloPE (Feb 2, 2007)

There was an engineer :whipping: at my old firm that kept his handy all of the time. Everytime the computers would go dow, he would come out of his office and ask if anyone needed to use his slide rule

Numerous times he tried to show me how to use, but being the "best available technology" guy that I am, I totally refused to learn.


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## Fudgey (Feb 2, 2007)

I can play the slide whistle!


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## grover (Feb 2, 2007)

I can multiply/divide on them, but I just can't figure out the graphing or matrix functions :whipping:


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## Guest (Feb 2, 2007)

My supervisor gifted his old slide rule to me. It is one of those things that I intend to 'take up' once I have time. :whipping:

JR


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## Art (Feb 11, 2007)

I used one in college...calculators were too expensive, and could not do logs, ln, trig or hyperbolic functions at the time...

a professor once said about calculators, a wrong answer to 8 decimal places is still a wrong answer...

no calcs allowed, do everything long hand and leave in radical form....that way he could see if we grasped theory/problem set-up, rather than just crunching numbers...


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## RIP - VTEnviro (Feb 12, 2007)

I wouldn't even know what one looked like.


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## MetroRAFB (Feb 12, 2007)

^^^^^^^It looks just like an abacus, dusty and unused. I must admit, there is a tiny part of me that is mildly interested in knowing how a slide rule works, but not interested enough to put forth the effort.


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## JoeBoone82 (May 31, 2007)

Some of the engineers I work with think it's crazy that us young engineers have never seen or used a slide rule. I think it would be neat to learn, but I have no idea. I've never been around one.


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## bigray76 (Jun 1, 2007)

I have my grandfather's slide rule in it's nice leather case. It is one of the ones that does just about everything. I also have a cheaper plastic one that he used at home which does the basics. I figured out how to use them years ago, but haven't used them in a long time.

-Ray


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## LXZ (Jun 1, 2007)

JoeBoone82 said:


> Some of the engineers I work with think it's crazy that us young engineers have never seen or used a slide rule. I think it would be neat to learn, but I have no idea. I've never been around one.


I want to learn too but never had a chance.


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## Mike1144 (Jun 5, 2007)

They have virtual ones on the web somewhere.


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## Old as Dirt Geo (Jun 5, 2007)

My grandfather, who graduated in 1936 from Michigan Tech with a mining eng degree, always tried to teach me how to use a slide rule when I was at Tech. In his opinion using a slide rule made you think about your calculations and therefore less likely to make stupid errors. He also said the best part was that it didn't run out of batteries in the middle of an exam. So until the day he died in 1989 he always used a slide rule and never owner a calculator.

Here is a link to some virtual slide rules if you a interestered.

http://www.antiquark.com/sliderule/sim/


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## umjeffr (Jun 5, 2007)

FusionWhite said:


> Thats what I thought the first time I looked at it. For multiplication and division you can ignore most of the scales and its actually pretty easy. I found a website that explains the theory of how a sliderule works and it was extremely interesting.


can you share that website. i have two of my dad's from his engineer school days and would like to scare the new guys in the office by breaking it out in front of them. HAHA


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## Guest (Jun 5, 2007)

Old as Dirt Geo said:


> In his opinion using a slide rule made you think about your calculations and therefore less likely to make stupid errors.


In a real sense he has a valid point. I see A LOT of kids coming out of college today who only know how to punch numbers on a calculator.  It makes for a very poor engineer if you don't have an idea as to what the range of values should be as an end result of performing some sort of mathematical operation (e.g. add, subtract, log, trig, etc.). Having an idea of the expected outcome provides the first line of proofing your work - a skill that is VERY MUCH IN NEED these days.

Thanks for the link!! :thumbs:

JR


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## bigray76 (Jun 6, 2007)

jregieng said:


> In a real sense he has a valid point. I see A LOT of kids coming out of college today who only know how to punch numbers on a calculator. :blush: It makes for a very poor engineer if you don't have an idea as to what the range of values should be as an end result of performing some sort of mathematical operation (e.g. add, subtract, log, trig, etc.). Having an idea of the expected outcome provides the first line of proofing your work - a skill that is VERY MUCH IN NEED these days.
> Thanks for the link!! :waitwall:
> 
> JR


Very true... a lot of our new hires here have no concept of the numbers that they are cranking out and can't look at them to think that something may seem out of whack.

-Ray


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## Enginnneeer (Jun 19, 2007)

Old as Dirt Geo said:


> My grandfather, who graduated in 1936 from Michigan Tech with a mining eng degree, always tried to teach me how to use a slide rule when I was at Tech. In his opinion using a slide rule made you think about your calculations and therefore less likely to make stupid errors. He also said the best part was that it didn't run out of batteries in the middle of an exam. So until the day he died in 1989 he always used a slide rule and never owner a calculator.
> Here is a link to some virtual slide rules if you a interestered.
> 
> http://www.antiquark.com/sliderule/sim/


Cool link. Thanks.

I surprised some 'older' engineers when in a meeting they brought up the slide rule subject and I knew what it was. My dad has one in his office at home and one day he let me see it and try to figure out how to work it.


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## zeteckat101 (Jun 29, 2007)

Enginnneeer said:


> Cool link. Thanks. I surprised some 'older' engineers when in a meeting they brought up the slide rule subject and I knew what it was. My dad has one in his office at home and one day he let me see it and try to figure out how to work it.



The website with the sliderule is quite cool.


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## benbo (Jun 30, 2007)

I am pretty old. I used a slide rule in high school physics. As a result of that I got really used to scientific notation and exponent operations, because the slide rule really is only effective for signifiant figure operations, IMO. As a result, I still do a lot of those manipulations in my head even when I use my calculator. THat way I can tell if my answer seems reasonable, or if I keyed in something wrong.


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## mudpuppy (Jun 30, 2007)

Old as Dirt Geo said:


> My grandfather, who graduated in 1936 from Michigan Tech with a mining eng degree, always tried to teach me how to use a slide rule when I was at Tech. In his opinion using a slide rule made you think about your calculations and therefore less likely to make stupid errors. He also said the best part was that it didn't run out of batteries in the middle of an exam. So until the day he died in 1989 he always used a slide rule and never owner a calculator.


How ironic: A co-worker of mine, who also graduated from Michgan Tech (but about 40 years after your grandfather) likes to corner the new engineers in the office and tell the story about the time he was taking a final exam and his caluclator's batteries died and he had to pull out his trusty old slide rule and it saved the day. This is invariably followed by "I think I still have it around here somewhere," rooting around in his desk and then spending half an hour showing how to use it. I wouldn't mind learning how to use one; by the time I got to Tech in 1996 (and probably long before) sliderules were nowhere to be seen.


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## MetroRAFB (Jun 30, 2007)

^^^^^Your co-worker would have been better served by having the foresight to carry a couple of extra batteries with him in lieu of the dinosaur slide rule in my opinion. Seeing this thread again makes me wonder..........In 40 years will there be threads on boards like these "Do you know how to use an HP48?" I'm sure in it's day it was the shit, but technology continues to advance and I wonder why we all say it would be cool to know how to use a slide rule. How come? Atari was fun back in the day but it would suck if you tried to play it nowadays. It's no doubt a piece of engineering history, but it's just that, history.


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## mudpuppy (Jun 30, 2007)

MetroRAFB said:


> ^^^^^Your co-worker would have been better served by having the foresight to carry a couple of extra batteries with him in lieu of the dinosaur slide rule in my opinion. Seeing this thread again makes me wonder..........In 40 years will there be threads on boards like these "Do you know how to use an HP48?" I'm sure in it's day it was the shit, but technology continues to advance and I wonder why we all say it would be cool to know how to use a slide rule. How come? Atari was fun back in the day but it would suck if you tried to play it nowadays. It's no doubt a piece of engineering history, but it's just that, history.


This took place back in the late 70's so the slide rule wasn't quite the dinosaur it is now, but you make a good point about the spare batteries.

Funny thing about the Atari--I bought one a few years back on Ebay thinking it would be great nostaligic fun, but the fun wore off after only a few days. It's just been gathering dust for several years now.


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## benbo (Jun 30, 2007)

You do not need a slide rule to get the knowlege, but some knowlege about arithmetic beyond pumping numbers into a calculator is of value. I tutored the SAT for several years, and a lot of these kids couldn't even add without some machine. I've been at cash registers before where kids could not make change without the machine telling them what to do.

Compared to any $5 calculator, the slide rule is about as useful as an abacus. But I have seen experts on a abacus beat people on a calculator doing calculations.


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## Guest (Jun 30, 2007)

^^^ You are absolutely right benbo. I was at a restaraunt a few weeks ago where my meal before taxes came out to just under $20. I watched the kid punch up the tax on a TI-83 and write the total ... $29.80. :blink:

It is very true that many of the kids now have absolutely NO IDEA to tell if a calculation is in the ball park so to speak. ldman:

JR


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## mudpuppy (Jul 1, 2007)

jregieng said:


> ^^^ You are absolutely right benbo. I was at a restaraunt a few weeks ago where my meal before taxes came out to just under $20. I watched the kid punch up the tax on a TI-83 and write the total ... $29.80. :blink:


Wow a 50% sales tax! That's even worse than Canada (14% over there in Ontario). I'm never visitng whereever it is you are!


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## grover (Jul 2, 2007)

mudpuppy said:


> How ironic: A co-worker of mine, who also graduated from Michgan Tech (but about 40 years after your grandfather) likes to corner the new engineers in the office and tell the story about the time he was taking a final exam and his caluclator's batteries died and he had to pull out his trusty old slide rule and it saved the day. This is invariably followed by "I think I still have it around here somewhere," rooting around in his desk and then spending half an hour showing how to use it. I wouldn't mind learning how to use one; by the time I got to Tech in 1996 (and probably long before) sliderules were nowhere to be seen.


When feverishly running generator fuel-consumption/runtime calcs the other day during a storm, it dawned on me that my solar powered calculator doesn't work terribly well when the lights are out. Not that I couldn't do simple long division on a piece of paper, but somehow that didn't occur to me as I repositioned the flashlight to try to illuminate the solar cells and see the faint imprint of digits on the LCD.


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## singlespeed (Jul 2, 2007)

MetroRAFB said:


> It's no doubt a piece of engineering history, but it's just that, history.



Let me throw out another perspective - I know you're a gun fan - do you have any "older" pieces that you're especially fond of in your collection?

Slide rules are like that to us older folk. The simple elegance of the technology that comprises the slide rule is appealing to me. ld-025:


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