You can make it on a lathe from plain pcb. Turn 4 rings (or etch it if you like) on it. Make for the other side a pcb on which you can solder 4 phosphorbronze sliders at 90 degrees interval, they will be somewhere hanging around in a modeltrainshop as spare parts. Make an axle on one side, a bearing on the other side and you're almost there.
Then give it to the kids and see how fast they brake it. |