Even if almost tragically impractical in a world where digital calculators are cheap as chips, mechanical calculators and their big mechanical computer brethren remain an absolute marvel of engineering. Using nothing but elements like simple gears their motion is used to calculate everything from a simple multiplication to the proper targeting instructions for an Iowa-class battleship’s guns.

This fascination, along with the mind-bendingly high prices for commercial digital calculators led [3D all Workshop] to spend 2 months on designing his own mechanical calculator. Fully FDM 3D-printed, of course.

In the video the design process and troubleshooting step are covered along with the workings of the mechanisms for both addition and multiplication. While this may seem simple, basically converting numbers of rotations into a final indicator position, aspects like carrying a digit and adding a multiplication feature to the mechanism require some proper engineering.

Of course, using FDM printing for tolerance-sensitive things like gears meant that a lot of time was spent redesigning aspects of the mechanism, going through about a hundred design iterations until it worked, with the help from a bit of lubrication.

Naturally this isn’t the first 3D-printed mechanical calculator, not to mention ones made from wood, but always it’s pretty cool to see one made from first fundamentals.