Alright, so this design isn't entirely my own. I got the idea from one of those 'Gopher' things that the Oxy-clean guy sells. It's real simple, and I've built this with erector set pieces to test, and it works great. The grey metalish box on the long shaft portion represents a rack gear, which should be turned by a servo or whatever you want. The fingers at the end should be made immobile, just put screws in the other holes. Don't forget washers also. Lemme know what you think or if you have any questions.