Lego PCB

Lego holes

I have been experimenting with adding Lego compatible holes to the PCBs. The size is critical. Since the fiberglass is rigid and has no flex, the ABS Lego pieces either fit or they don't. There is no squeezing them in.

4.9mm holes are is just a tiny bit loose. 4.8mm is too tight. You can take a small round file and slowly enlarge the holes for a perfect fit, so starting off too small may be better than too large.

The final size probably varies due to the manufacturer's tolerances. What might be perfect on one order may be too big/smaller the next time.

I don't have a lot of Lego blocks to experiment with. This Gherkin base plate has 4.9mm holes on 8mm spacing. The blocks hold in well. Some tighter than others.

Closeup of the holes.

Another experiment. This one with 4.8mm holes. The blocks will not fit without some filing to enlarge the holes.