The original pins I found (they are since deleted) had tiny holes in the middle that made the cross-section a little strange and were a bit faceted, so I copied the angle of the pin slot and redesigned the rest using max facet cylinders in Tinkercad.

I also included the .stl file for the pieces I used to make each pin. To make your own pins make the cylinder the length you want (8 mm per lego stud), center the disc and wedge (make the wedge a hole) on the ends, and put the doughnut in the middle for the stop.

This is wrong - T̶o̶ ̶p̶r̶i̶n̶t̶ ̶I̶ ̶p̶u̶t̶ ̶o̶n̶e̶ ̶e̶v̶e̶r̶y̶ ̶6̶ ̶m̶m̶ ̶i̶n̶ ̶C̶u̶r̶a̶ ̶s̶o̶ ̶t̶h̶e̶y̶ ̶j̶u̶s̶t̶ ̶t̶o̶u̶c̶h̶ ̶a̶n̶d̶ ̶i̶t̶ ̶s̶e̶e̶m̶e̶d̶ ̶t̶o̶ ̶w̶o̶r̶k̶ ̶w̶e̶l̶l̶.̶

Update - To print them so they don't snap off when you try to use them, lat them flat with the slot vertical and set the z-position to -1 mm so they will sit slight into the build plane and cut off the first millimetre. In this orientation they will print better and be a lot harder to break. Depending on your printer, you might need to scale it down a few percent to get it to fit properly.

Print Settings

Printer:

Ender 3

Rafts:

Supports:

No

Resolution:

Infill:

20%

Filament:

Hatchbox PLA

Black

Category: Construction Toys