Round Base, Rigid PVC
Here's a CNC*-machined round base. made from 6mm (about 1/4") thick expanded rigid PVC. This stuff is very lightweight, yet is amazingly strong. It generates little static electricity (as opposed to acrylic, which generates static copiously), and can be readily cut and drilled.
You can stack several of these discs to create multiple "decks" for your robot. Unlike metal or most other plastics, these PVC discs add little weight of their own. You can stack 4, 5, and even more discs to create a multiple topping 'bot! (Though we recommend no more than three decks, to minimize the chance of the robot tipping over.)
The bases are available in several diameters, to suit most any tabletop robot design: 10 centimeters (a shade less than 4", ideal for mini-sumo), 5", 6", 7", and 8", with pre-drilled mounting holes. The center hole is 3/8" diameter; there are 12 equally-spaced 1/8" diameter holes 1/2" from the outside rim of the disc (1/4" for the 10 cm and 5" discs). You can, of course, drill additional holes as needed.
Available in colors. Click here for sample colors (colors are shown approximate).
*CNC stands for computer numerically controlled. To prepare these bases (and many other products we provide), we use a computer operating a high-speed precision CNC router that has an accuracy of greater than 0.001".