On the latest flea market in constance I found a rare lego box: One of the first lego technic boxes with controller and motors.
When I was younger, I always wanted to own one of these technic boxes. So I bought it for my daughter spending peanuts in comparison to the original price.
The box seemed to be complete and almost unused. The controller was working and the two motors, too. The only problem were some missing toothed racks:
Our bananabox full of lego parts didn't contain enough of these bricks, so I decided to use my reprap to complete the set.
I looked for a stl-file on thingiverse, but exactly this brick was not available.
Armed with a caliper and openSCAD I created my own file and printed it.
As expected, it didn't fit correctly, because: Never mess with lego accuracies.
Lego parts are at least made with an accuracy of about 0.05 mm.
After tuning the values to a fitting brick, we were able to complete our lego CNC robot for my daughter.
Surprisingly she was very excited by this robot and played around a whole afternoon - and I thought, 9 years old girls play with dolls!
A shorter version of this brick is also possible. It was simple cut in the middle.
If you want to print one of these, just download the openSCAD file on thingiverse and tune the values according to your reprap 3D-printer.
Just download the files on thingiverse.
Greetings from the lake of constance