My son Robert (and me)(and me) wanted a faceplate for his new guitar hero 3 guitar, after looking at some we thought that it would be a shame that he would be stuck with the one he had chosen, so we thought outside the box and decided it would be an interesting make one, and then to post on-line, it is quite and easy project and it has been quite informative and fun for Rob and me.
Step 1: Mark out faceplate
Step 2: Making the grinding table
be careful drilling not to press hard because perspex cracks really easy, put it between 2 pieces of wood to drill to help it but no need to be too exact as they are just to get the grinder in.
Next bit to do is to make up your grinding table, I used a dremel clamped in a workbench, and then we raised the height with bits of wood to get just the cutter showing.