The washers used as touch switches with the LED game require that a wire be soldered to their undersides.  That wire has to then feed through the hole which was pre-printed in the button.  Locating the solder point was critical.

I took the 3D model for the button and created a version that had a square exterior, rather than round.  I then placed that in the vise in my mill, located my drill bit over the hole, and drilled out the washers quickly and accurately.  Using the 3D printer to create a jig for use in my machine shop is just one more reason to like my 3D printer!

These pictures show me placing the jig in place, locating the hole with the drill bit, and then drilling out the washer: