3D Printed Curta

Marcus Wu:

Not exactly "actual size" -- looks like 4x or 5x -- but wow, I am amazed this thing works at all! Look at how grainy and fibrous the print is. This feels like someone trying to replicate a mechanical wrist watch using flint tools. Metallurgy? Who needs it. This is as bonkers as "Transistor-level Simulation 6502 in Javascript" or "Octophant, I Should Not Be".

Do you feel cheated every time you see something that is "3d printed" but is full of steel screws, springs and bearings? I do. Like, "It's a paper airplane! Except for the internal combustion engine." The lambda that is not self-hosting is not the one true lambda.

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8 Responses:

  1. Noah Friedman says:

    I may feel cheated, but I still want one. I am too chicken to take my real one apart.

  2. J. Peterson says:


    It's 4x size. Printing this at Shapeways would produce a finer finish, and cost a few hundred $. Still, that's less than the going rate for actual Curtas on ebay (running well into four digits now).

    I wonder if a finer SLS print would allow a smaller scale. Maybe 3x or 2x? Would cut the printing cost exponentially as well.

    There's another project on Github trying to re-fabricate the Curta in metal. Doesn't appear to be as far along though.

    See also: 3D Printed Tourbillon Watch.

    • Tim says:

      Still, that's less than the going rate for actual Curtas on ebay (running well into four digits now)

      Christ, almost as bad as TB303s.

    • tfb says:

      It's odd they're so expensive: there were a lot of them (more than 100,000 I think) and they're very robust so long as you don't take them to bits. So, I suppose, either a lot were thrown away or taken to bits, or they're very desirable.

      (On the other hand the prices look compatible with Leica M3s, and there were 220,000 of those, so ...)

  3. rbj says:

    This is all well and good, but when is somebody going to 3D print Stephen King's Wang?

  4. Marcus Wu says:

    I am the creator of this -- let me clear up some things. It is 3:1 scale. The print appears grainier than it is. The plastic used is "natural color" which is slightly translucent, so what you are seeing is a little bit of the infill inside.

    As for the metal parts... I never claim it to be a "100%" or "fully" 3d printed device. I could have 3d printed the bolts and nuts, but they are common parts. The goal was to just to build a Curta so I used as much as I could find. The main reason I chose to 3d print is because it was available to me. If I had a CNC mill and lathe and the skill to use them, I certainly would have.

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