Lego Brick (Customizable), and tight snap-to fit

thingiverse

I'd tried printing quite a few of the Lego bricks available out there but tended to find them a little loose fitting. azzeloof's openscad design was pretty good, allowing for full customization of the brick size, although, the bumps, or knobs on top still didn't quite make for a tight enough fit. All I've done is add a variable to the SCAD file to increase the knob size from 4.8 to 4.9mm (you can vary this as you please), the hard work was basically done by Adam Zeloof in 2013. I've tested this on a Makergear M3 (not M2, as Thingiverse insists!) SE at 200 micron layer thickness, PLA, and it prints fine; the bricks snap together just as I remember as a child! Obviously you can print finer detail if required. As always, your mileage may vary dependent on printer/filament etc.