Paper Calculators: The Lightning Calculator, 1932 and the Color Helm, 1940

I loves me some paper calculators, yessir. My first one I remember was a simple slider that did multiplication and came out of a box of cereal in 1970-something. The idea of a computer constructed out of paper fascinated me immediately, and I wore that cereal box calculator to shreds as a kid. Later in life, I had much occasion to use a Proportional Scale, which is a calculator for proportionally scaling images into enlargements or reduction for darkroom work.

I’m still fascinated by them, and today I found some really nice examples in great shape for a couple bucks.
(these are actually very high-resolution scans. to see them full size, save them to your computer or right-click and select “View Image”)

I present to you:

The Lightning Calculator Type A
Published by The American Radio Relay League, Inc. (1932)

lightningcalc-type_a-front lightningcalc-type_a-back

The Lightning Calculator Type B

lightningcalc-type_b-front lightningcalc-type_b-back

The Color Helm
Published by Fiatelle, Inc. (1940)
color_helm-front color_helm-backI call your attention specifically to this passage of text that accompanies the Color Helm:

color_helm-featYeah, FOURTY runs through the press. In those days it woulda been a single-color press. Let me tell ya, speaking as a printer, that *would* be one heck of a heroic printing job.

Updated: January 1, 2020 — 1:00 pm


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  1. These ARE impressive, especially the Color Helm. I’m old enough to have been introduced to slide rules in grade school, but I never really understood the logarithmic principles — they told us what to do, but not why.

  2. I remember quite a few paper calculating aids. I grew up with the slide rule and watched the caclulator develope during my second year of college and then from big giant main frames (where one needed to schedule their processor time to use them) to the advent of what we can now carry in our pocket.

    Love those Lightning Calculators. I’ve never seen any like that before. I’ve been playing with radio since I was 10 when I got my first ARRL Handbook and got on the air.

  3. WOW! Those are cool! I collect specialty slide rules, so that Ohm’s Law one is especially intriguing to me.

  4. Oh wow, I don’t think I’ve seen paper calculators before. Like Richard, I do remember the slide-rule but unlike him, I understood nothing, be it the what or the why!

  5. Those are great to look at. They evoke scientific engineering optimism (for me). Analog technology and still fully functional I expect.
    The typeface on the color is very period. Thanks for posting these.

  6. Deliciously analog and yes, as functional as any slide rule in good condition. Luckily, they are well-preserved – having been stored in protective envelopes for apparently their entire existence. They show little usage wear, and the colors are bright.

    I’m certainly going to start collecting these things- they represent to me a distillation of a book’s worth of knowledge into a one-page program focused on solving a single set of problems. Having a bound book full of these things would make me feel like I owned a volume from the library of Prospero. It would be imbued with a very unique sort of magic.

  7. If anyone is interested, I have several such types of calculators for sale. You can contact me a (email redacted – please contribute to conversation instead of just using my blog as a sales tool)

  8. Hey there,

    I’ve been fascinated with these lightning calculators lately. I found this blog post and your scans, and made a reproduction!

    But, some of the numbers on the bottom wheel are obscured….any chance that I could talk to you about getting a better series of pictures that I could composite?

    I’d make you a copy of course!

    1. hmmn, well, to replicate them, I would think they’d have to be taken apart and scanned, as they are multiple paper wheels attached together with a solid brad. I’d have to destroy the attaching brad to get them apart, and that would be sad. ):

      1. I got pretty far on Type B (the one I am interested in) with your original scan and photoshop! I think that it would be possible to do it non-destructively by taking some pictures with the wheel and pointer at different orientations and composite them, as well as a picture with a green paper skirt separating the wheel and the bottom card that would make it easy to isolate its actual shape. I could make this stuff and mail them to you or something.

        Here’s what I have done so far:

        Feel free to email me if you are interested, but if it’s too much of a pain no big deal :-)

        1. emailing. I scanned a few different turns and saved as Tiff of less image loss.. (:

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