Antique Electromechanical Calculating Machines

electromechanical calculator Hamann 505

The decision to use electronics for our calculating machines has long been decided.  However, that doesn’t mean that mechanical engineers didn’t put up a valiant, if ultimately futile, fight. [] has an interesting article comparing the calculating technology of the 1960s, such as the [Haman 505], to today’s iPad.

This comparison and pictures were made possible by [Mark Glusker]‘s excellent collection.  These models can be divided into two categories, rotary calculators, and printing calculators. According to [Mark]‘s site, the printing calculators stayed on the market a few years after the rotary calculators, which were off the market by 1970.

Although we may never see machines like these made again, anyone even a little bit mechanically inclined would be hard pressed not to be inspired by this collection. Be sure to check out the video of a [Madas 20BTG] calculator after the break to see what one of the rotary models looks like in action!

Thanks [Caleb] and [Adam] for the sources of this article!


  1. ultimatereality92 says:

    It sounds and looks so beautiful.

  2. LordNothing says:

    wow, that video is like porn for geeks.

  3. Mike bradley says:

    I actualy used one of these as a kid, but it was lever driven. Weird is I am only 40yrs old, calculators were around.

  4. Oliver says:

    I have a mechanical (no electrics at all!) calculating machine here at my home. :)

  5. leeahart says:

    The essence of engineering is to Make Things Work. If it’s 1940 and you want a calculator, how else are you going to do it? Sure they’re big and clunky — but they work! By that standard, they are a success! Millions were built, and ones that were properly maintained still work today!

    Don’t think they were all large, either. The Curta pocket calculator (designed in 1948) is purely mechanical.

  6. Praetor1 says:

    Wow, it’s cool to think, on the other side of the spectrum, if we did not find the technology we have to day, everything would be made mechanical…including television, at one point. Cool video. Think Charles Babbages Difference engine, it’s funny his computer couldn’t be finished because the technology to do so didn’t exist at the time, but the mayans could predict the end of the world (or their clock) with sticks and stones? they didn’t even have the technical mentality to invent the abacus…but they know when the end times to pass?

    • n0lkk says:

      Of course the Maya probably didn’t predict the end of the world. Counting aids similar to the abacus appear to have been developed in the Americas that suited to needs of the inhabitants of the the time

    • n0lkk says:

      Last spring while cleaning out my mom’s garage I came across a manual adding machine. Without a tape in in it I couldn’t determine if it was functional, and because the edict was get rid of everything that was no longer practical, to the landfill it went. there is a limit to what I can warehouse myself, adding to the layer of stuff my family has to deal with when I kick the bucket.

    • Dan J. says:

      Wow, it’s cool to think, on the other side of the spectrum, if we did not find the technology we have to day, everything would be made mechanical…including television, at one point. Cool video. Think Charles Babbages Difference engine,

      Welcome to the world of steampunk. Google is your friend.

  7. XOIIO says:

    I don’t know what the hell I would do with it but I want one!

  8. austin says:

    little known fact: that device is in fact the head of the doctor’s dog K-9.

  9. Lance says:

    I got a printing calculator from Victor, if only I had the power cord for it.

  10. The K says:

    While looking at this article my roommate came across and said: “Hey, my mom worked at curta A.G. in liechtenstein…”. He walks off and comes back with one of these:

    The company’s history is pretty entertaining yet tragic.

  11. Chris says:

    I had an uncle who “recalibrated” these calculators for a while as his job. Occasionally, one of a calculator’s gears might skip a tooth, and that one tooth offset would introduce errors into the results (and we thought the Pentium floating-point problem was a new phenomenon!). He’d realign everything, and the calculator would be back in business again.

  12. Chris says:

    There is a great chapter in “Accurate Tool Work” by Goodrich and Stanley about the precision required to make the tools/jigs that were necessary to mass produce these kinds of calculators

  13. Jim Harvey says:

    There was one of these rotary machines in the Engineering Department at Michigan Bell when I started in 1970. It could mechanically extract a square root! If you gave it a hard problem like a root with an irrational solution, it would run for many minutes before coughing up an answer.

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