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My adventures in 3D printing: Prime number sieve

At work we’ve got a 3D printer. In this series of posts I’ll share some of the designs I’ve made.

Hand holding a stack of 3D printed squares, with holes cut out.

This is something I’ve wanted to make for a long time: a literal sieve of Eratosthenes.

This is a collection of trays which stack on top of each other.

Each tray has a grid of holes, with some holes filled in. The tray with a “2” on it has every second hole filled in; the tray with a “3” has every third hole filled in; and so on.

Four trays, corresponding to numbers 2,3,4 and 5

When the trays are stacked together, the holes you can see through correspond to prime numbers: every other number is filled in on one of the trays.

I went through quite a few iterations of this design. The first version was a series of nesting trays. After printing it, I realised that you might want to put the trays in a different order. After that, I did a lot of fiddling with different ways of making the plates stack on top of each other. The final version has sticky-outy pegs at each corner, and corresponding holes on the other side. I had to add a fair bit of margin around the holes so the wall didn’t go wiggly when printed.

You can download .scad and .stl files for the prime number sieve at Thingiverse.

(will not be published)

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