The ShopBot Three-Axis Zero Plate accessory is the BEST the thing that I've purchased for my desktop. Now I can concentrate on CLAMPING my material with sloted plywood clamps (1.5 X 4 X various thicknesses) without worrying about where the xy zero is. These clamps are held down with nylon screws. T-nut (approx 180) are installed on the back of the 24 X 18 X 3/4" MDF spoilboard spaced in a 1.5" square pattern. Then I use the "three-axis zero plate" to ZERO xyz. $149
Thanks ShotBot!