If we had a fully-equipped machine shop we might have gone that route, but we work in a woodshop and don't have a lot of money for paying someone else to do welding and machining, so we had to choose between wood and bolting together stock aluminum bits. My hobby is woodworking and I built a couple of sample components to show the students that wood can be light, stiff and strong if you design around its strengths. (For example, an 8-foot 2x4 weighs around 10 pounds. For comparison, a piece of solid aluminum stock a little over 1" square would weigh around the same -- but it would bend a lot easier. Of course, you wouldn't use solid aluminum bar stock, but we didn't use 2x4s either.)
Our towers are I-beams with 4-inch webs glued into .25-inch-deep grooves in the 2-inch wide flanges. We used zero-void 1/2-inch Meranti plywood. The two towers are joined by glued-and-screwed plywood panels for stiffness, and, frankly, to give us a big flat surface to decorate on the front. Blocks of pine are glued into the I-beams wherever we wanted to attach braces or the bearings for the arm mechanism. The bearings are captured by holes drilled into the insides of the pine blocks.
The electrical systems are mounted on 1/2-inch construction plywood and the tetra-gripping system is mounted on 1/2-inch construction plywood reinforced in key places with a second layer glued into place. If we hadn't been in such a hurry, we would have used 12mm Baltic Birch plywood.
The robot was built undersized to allow us to attach a bumper system within the 28x38 inch limit. To make sure we stayed within the box, we milled 1.25 inch side bumpers out of fir. The robot was a little too close to 38 inches to use this on the front and back, so we substituted 4/4 red oak. The corners are reinforced with heavy steel strapping usually used as a construction brace.
By the way, in the photo above, the tetra is being held over the back of the 'bot. We score on the other side.
Just thought you might be interested in some of the details of our Old School technology...
I would much rather educate the audience than dumb-down the game. - dlavery [more] 
22-02-2005, 18:47
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