The monitor frame is just a simple 12 x 18 inch box frame, created out of four strips of ½-inch MDF. I would suggest that each frame wall have a depth somewhere between 1.5 inches and 2 inches, depending on the depth of the LCD monitor. I chose 1.5 inches, knowing that the depth of the monitor is slightly larger and would encroach on the main arcade casing.

 

Hence, the box frame consists of four strips of wood:

 

 

The pieces were initially sealed in a box shape by carpenter's glue, then I secured them on each of the four corners with small screws, two in each corner.

Here is the monitor frame, side-by-side with the monitor cover, as well as the monitor (Compaq w17Q LCD Flat Panel Display) itself.

 

To support the monitor, I used eight L-braces (also called “corner braces”). The first four, which are the outer gold-colored braces in the picture below, serve as outside guides for the monitor itself. These keep the monitor from sliding from side to side. The vertical walls of those braces were placed around 1/2-inch inside the wall of the frame, flush with the top surface, to match the width of the Compaq w17Q.

 

The four silver braces are placed deeper into the frame, and actually hold the monitor by allowing the back casing to rest on them. The positions of the last four are arbitrary, and depend on the shape and depth of your monitor. My advice here is to place the monitor and the housing frame upside down, with the outside guides in place, and simply mark off where you'd like the support braces to be. If you're concerned about the cosmetics of the sides and back of your monitor, line all 8 of the metal braces with small pieces of felt or plastic cap guards.

Below is a picture of the monitor inside the housing frame, with the cover on top, similar to its appearance in the final MAME cabinet. Note that the inside edges for the monitor cover are not perfectly straight. I'm a bit of a klutz with a jigsaw. Use the sanding technique I described earlier and learn from my mistake, or line the edges with sliver edge guards (often placed on the sides of automobile doors to protected them) to make the inside cuts look straighter.