Wow, small world eh? Yup, the drawer slides allow the work table to move up & down too much.
I guess I'll build another one someday but so far I have only been cutting out sheet balsa & ply model airplane parts and I can live with it's faults.
The basic design came from Dan Mauch's article "Cimple CNC Circuit Board Driller" from Dec. '94 Nuts & Volts mag. Hobby CNC has come a long way since then!