[Roy G. Biv]

I have dramatically improved the manual az/el motion of my Zhumell ten-inch Dob by incorporating easy to obtain and install off-the-shelf parts. I hope that these modifications will be of use to t hose Dob owners who are unhappy with jiggling images when using, for example, a 2.3 mm eyepiece.

I don’t think much narrative is necessary being that “a picture is worth a million words.” Besides, Dob owners will immediately recognize the rationale for the modifications.
For smoother azimuth movement all you need are these principal parts:
1. Cut and bolt a shorter-radius, wooden fixed-disk to the platform.
2. A bicycle chain and sprocket.

For smoother elevation movement:
1. Fashion and attach a wooden frame to the rocker box.
2. Get a 3/8" threaded steel rod, a threaded knob, and a pivot brace.
Included also, are pictures of other mods that may be of use.

I will be glad to respond to requests for more info.

Your northerly brother,

Roy G. Biv