LEGO compatible Letters and Numbers

These LEGO compatible letters and numbers are printed lying flat on the printer bed and can be snapped onto Lego bricks standing up.

I designed them to create custom nameplates for the guests of my daughters birthday party. They are cool as gifts and decorative as well.

There are two small gaps that need to be bridged when printing, but this works well on my machine. Despite the small size, the parts are quite robust. Snapping them onto a Lego brick is a bit stiff but works reliably and gets easier after a couple of uses.

I tested printing the parts on two different printers and with two different materials (PETG and PLA). PETG is better as it is more flexible, but PLA works too. Due to the tight-fitting requirement with Lego bricks, I cannot guarantee that the prints turn out well on all printers.

Printing instructions

• Print lying flat on the bed (STLs are already oriented correctly)

• Support: No

• Nozzle Size: 0.4mm (the models are optimized for that size)

• Layer height 0.2mm (the models are optimized for that layer height, please make sure that the first layer has a height of 0.2mm as well)

• Material: PETG (preferred) or PLA (tested to work ok). Other materials are not tested.

• Perimeters 4 (the letters and numbers are 8 perimeters tick for the most part)

• Solid Layers: I usually print with 5 top and bottom layers. Set to 20 to have the whole model solid with no infill.

• Infill: does not matter much, only the heart and star use infill in a noticeable way.

• Ironing: Enabled for all top surfaces (this is not a must, but the letters look nicer with ironing enabled, it smooths over the little gaps and “fills” the whole top surface)
  

Edit from Dec-31, 2025:
Added a new letter, the Spanish Ñ.