I made some progress on the trunions and base this week (ie, the altitude and azimuth bearings). I'm still waiting for a couple of components from McMaster-Carr to get here before they will be complete.
The trunions are two large arcs of 13-ply wood. They are positioned so that their center is 14 inches above the mirror surface, which is approximately where the center of gravity of the optical tube will be. This makes the mount points of the mirror cell 17 inches from the center, and so I made the inner and outer radii of the trunions 14 and 20 inches respectively. Hopefully this thickness will be sufficient to support the 60 lb optical tube - if not I may need to add some aluminum struts. I will eventually need to put a hinge and latch in the middle of each trunion, since there's no way this would fit into my car at the present time. This issue makes me debate the merits of an "ultra-compact" design without a dedicated mirror box, vs the more traditional Dobsonian design, but I still think I'm happier this way.
The base is a a relatively simple palette-like structure, using the complementary pieces of plywood left over from making the trunions, held together with framing lumber 2x4's. It will eventually sit on a lazy-Susan turntable from McM-C, en route currently. The footprint of the base is 24 x 28 inches.
At some point, I need to buy the teflon pads and plastic molding that makes the altitude bearing smooth to maneuver.
