(Last updated December 02, 2000)
The photographs below show my platform in various stages of completion. The platform was designed specifically to preserve the height of the eyepiece on my Telescopes and More 12.5" F/5 dob, which is just right for my height. The scope came with a ground board that stands 3" tall, including feet. I figured I could stand to gain no more than 1/2 inch without requiring a stepstool for zenith viewing. The images will help explain my approach for getting the roller bearings as low as possible. The north sector is conical, the south is cylindrical. I owe a debt of gratitude to Chuck Shaw of Texas  and Howard Banich of Oregon for design assistance and encouragement, respectively.

The platform now has greatly improved stability over the initial trial. Lots of reinforcing, and a fourth foot at the south end to take out the twisting action. Total height is about 3.5 inches, I can accommodate this well. The sector gear is made of softish plastic (Sculpey Super Flex modeling clay) and seems to work very well! It requires a fair amount of force to keep the screw engaged with the sector gear, but this is probably typical. Modeling compound was quite easy to use compared to epoxies. The compound is cured in contact with the screw, but does not stick. It remains flexible enough to bend to the shape of the drive sector. Do not use standard Sculpey: Although it flexes too, it can be carved with your fingernail and would wear out in no time.
 
 

I'll update these images as I make progress and if I find the time. A picture is worth a thousand words, no? But I'll bet a picture demands a thousand words too. Please contact me if you want more info.  Rob Brown