I made a simple box frame out of 1" sq pine strips, with simple glued and screwed butt joints. A hardboard top, bottom and left and right sides made it rigid, a simple handle was screwed directly into additional strips running horizantally across the frame halfway up each side the frame each side, with vertical pieces above them to act as a brace. I used a piece of rack gear to make sure I had the critical internal width dimension right (yes, it is exactly 19" between the two inner faces of the vertical strips)
For mounting the gear, I put the completed frame on its back, so I could slot my gear in from the top , and marked the hole positions with a pencil. These were drilled with a 5/16" bit, and the gear secured with M6 bolts, rubber washers (between the gear and the wood) and nuts from a hardware shop. I painted the whole thing black. Cost less than $10 and took a couple of hours.