Here’s a quick template I created to help mark out the hole in the battery boxes necessary to accommodate the NPC-2212 motors and the JAG/Dave Painter Foot Drive System.
Download and print the file at full size on 8.5″x11″ paper without scaling. I can’t stress enough not to scale or alter the margins.
I used a Dremel to cut out the hole and if I had this template to start with I’d probably saved myself a few hours work and a bunch of cutting wheels.
Note: Your mileage will most likely vary. This is not an official builders club document but based on my experience in cutting my JAG Battery Boxes. Everyone has a slightly different way of building a droid, so best check then double check all measurement before cutting.