This is a customizer for creating LEGO® compatible rectangular bricks with text engraved on the sides (all 4 sides). You can of course also use it to create bricks without any text. It can create bricks as small as 1x1x1 (plate height) or as large as 48x48x18 (6 normal bricks high).
All dimensions are accurate, but it has a tolerance parameter so the dimensions can be tuned to your printer/filament so that they have a perfect fit with one another and with real LEGO® blocks. Real LEGO blocks have a horizontal play of 0.2 mm so that they can be connected to one another. So a 4x2 brick is 31.8x15.8 mm and a 6x2 brick is 47.8x15.8 mm, for example. The tolerance is in addition to the required 0.2 mm play and is subtracted from both sides of all walls so that the default tolerance of 0.05 would make the previously mentioned bricks 31.7x15.7 mm and 47.7x15.7 mm.
The customizer, by default, creates LEGO-sized bricks only. The large nameplate brick in the photos was scaled up in the slicer to 200% and then printed. I had adjusted the text depth parameter in the customizer to half the default so that when it was scaled up it was at the desired depth of 0.8 mm. This depth is recommended so that there are no extreme overhangs. The "LEGO Text Bricks" in one of the photos was just scaled up in the photo.
Note that since creating the bricks in the photographs I have added a parameter to specify the spacing between letters and by default they will be spaced a little farther apart than on the bricks in the photos.
2019-10-18 Update. I set all LEGO dimensions as adjustable parameters. If you are having trouble with the fit and need more control than the tolerance parameter provides, you can now override any of the LEGO dimensions.
If a brick will be connected to other bricks you don't want it to have an elephant's foot. I usually have the initial layer horizontal expansion parameter in Cura set to -0.2 mm to prevent elephant's feet, but for the LEGO bricks with a default tolerance of 0.5 mm this must be reduced to -0.14 in order for the under-tubes to be printed on the first layer.
For the best looking brick, you'll want the top surface of the brick part of the model to be a single continuous print from one corner to the other instead of going around the areas where the studs will be added in later layers. To accomplish this in Cura, set the Skin Expand Distance to 2.2.
The raison d'etre
I had been printing #2456 LEGO bricks as my filament samples, but they didn't indicate which filament it was so I couldn't differentiate between two similar ones. Thus the idea was born to put text on the side of LEGO bricks.