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Where can one still find a slide rule?

  1. Feb 4, 2015 #1
    I'm taking a history of mathematics course, and we talked about slide rules today, and now I want to learn how to use one. Where would I look for one? Any recommendations about which models/features to look for?
  2. jcsd
  3. Feb 5, 2015 #2


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    You can always try ebay. If you google 'slide rule', you can find an assortment of different slide rules for sale on Amazon.com.

    Just let your fingers do the walking on the World Wide Web. :)
  4. Feb 5, 2015 #3


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    Sad (for me) to think that they are nothing more than historical relics since us old guys used them all the way through college, but of course, modern calculators ARE functionally much better ... they just aren't as aesthetically pleasing. A well made bamboo based K&E log-log duplex trig slide rule looks like a work of art. Modern calculators look disposable.
  5. Feb 5, 2015 #4


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    Fixed it for you...
  6. Feb 5, 2015 #5

    Stephen Tashi

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  7. Feb 5, 2015 #6


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    Special purpose slide rules are still pretty common. I have three that I use at work. Here's one:
  8. Feb 7, 2015 #7


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    Russ Waters,

    That Ductulator looks like a nomogram, yet another anacronistic thing we don't use much anymore. But if it slides, I guess it is a sliding nomogram.

    In the field and in harsh environments, slide rules and nomograms still find use. I was a volunteer fireman. I made nomograms to help calculate pressures and flows for the pump engine. Coated in plastic, it could still be used in the wet at -40 degrees.
  9. Feb 7, 2015 #8
    I found this site about a decade ago. Stupid me (stoopud stoopud stoopud) ...I missed my opportunity to purchase a few New In Box absolute jewels. Gorgeous Japanese, German, British, French, and Russian slide rules. I kick myself every couple years or so for not acting on my whim to purchase some mint condition works of mathematical and engineering art.


    The next best thing are the many Java-language online sliderules that are fairly easy to find.
  10. Feb 8, 2015 #9


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    I still have my Post slide rule after 52 years. The bamboo, the faces, and the slide show no wesr, but one of the graticule glasses is broken.

    I recall how rapid the decline of slide rules was. In the 70s, K&E was king, and sales were strong. Then HP introduced the HP-35 scientific calculator. Only three years later, K&E donated their master dies to the Smithsonian.
  11. Feb 8, 2015 #10
    I still have two suits with pockets for a 5-inch slide-rule. I don't carry it, though ! My h-p 35 died, but the rule worked last time I used it (last century...) Best wishes 2 all
  12. Feb 8, 2015 #11
    Well, once you take the survivalist point of view, the slide rule is worth more than its weight in gold.

    And, a good 5" pocket model is great for making quick calculations and comparisons on the fly. Waterproof.
  13. Feb 8, 2015 #12
    I gave my old K&E log-log duplex deci-trig slide rule to my grandson just a few weeks ago. He was fascinated by it.

    One thing about slide rules is that their batteries never run down.

  14. Feb 8, 2015 #13

    Vanadium 50

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    EBay is an option. What you will find is that high quality rules can be very expensive, while more downmarket ones are less expensive (but often overpriced). A cheap plastic 5" Pickett will run you $10-20. From there it goes up into the hundreds.

  15. Feb 8, 2015 #14
  16. Feb 8, 2015 #15
    I didn't look for regular slide rules, but circular slide-rule templates are easy enough to find (Google: "circular slide-rule template"). I think I found mine here: http://www.hpmuseum.org/srinst.htm. I made one for the kids last month at home. Print out the templates to scale on card-stock, cut them out and put them together with a pin or something. At first, they said, "Isn't there an app for that?" ... "Yes. It's called a calculator. But this is how you do the math after the EMP during the zombie apocalypse to calculate how to restore order to the planet."
    I thought about printing one inside the course-pack I give to my physics students. If I make the next test open-book, but don't allow calculators, maybe they'll use it.
    Ooooh, here's an idea ... print the text in red and blue offset and include a set of 3D glasses so the slide-rule scales all appear at different distances .. that would be so geeky cool!
  17. Feb 8, 2015 #16
    The Curta mechanical calculator ws probably a high point in portable mechanical calculation buy one if you seei one. http://www.vcalc.net/cu.htm
  18. Feb 8, 2015 #17
    I recently found my K&E Decilon, in new condition. It's beautiful, both sides.
  19. Feb 8, 2015 #18
    A key difference between slide rules and calculators is slide rules don't store decimal points. If you're a structural engineer, for example, a calculator or computer might tell you that you need a 6.5-inch beam. A slide rule will tell you that you need a "65" beam. It's up to you to know if that means 0.65 or 6.5 or 65 or whatever. You can keep track of the decimals or just use your judgement.

    Another key difference is slide rules don't add or subtract in the traditional sense. That helped calculators make slide rules obsolete.

    The first commercial portable electronic calculators came out when I was a college senior. I was an early adopter and had to ask my professors if I could use it for examinations. None of them had seen one, and all of them asked if it made any noise. When I showed them it didn't, they had no problem with my using it.
  20. Feb 8, 2015 #19


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    Chemical Engineers use tons of Nomograms. Even today. Literally every handbook & textbook has one.
  21. Feb 8, 2015 #20
    I have this. The batteries never die and it is not fat fingerable.

    http://www.sportys.com/source/images/jQzoom/16562.jpg [Broken]
    Last edited by a moderator: May 7, 2017
  22. Feb 8, 2015 #21
  23. Feb 8, 2015 #22
    Slide rules are analog computers, not digital.
  24. Feb 11, 2015 #23
    Amazon UK has.

    Also ask on an army forum as they still use them for older artillery which hasn't got a computer. Not sure if they are general purpose ones or only able to do ballistic calculations.
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