I designed this motor mount to mount a 12 V DC motor to a piece of plywood. The motor can be found cheaply on ebay here http://www.ebay.com.au/itm/161777108766?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AI The dimensions of the motor are as follows Shaft diameter: 4mm Product dimensions: 25mm I made the hole in the middle 5.5mm to suit the fixed spacer on the front of the motor and it fits snuggly and would hold in place without screws for light applications. I printed it face down in pla with 10% infill with supports to support the base lugs with a raft and it took 39 minutes.