Family Home Page Machinist Home Page Shop Details Lathe Cleanup Projects

Motorized telescope Lens Caps

One requirement for my amateur astronomy hobby is to control the observatory and telescope equipment completely remotely, eliminating a 300-foot walk out to the observatory. Motorized lens caps for the telescope and guide scope are needed for fully remote operation.

I needed to machine splines on ¼" brass shafts to mate with motors that could be controlled remotely. These are the finished splines.


To machine the splines, I removed the three-jaw chuck from the lathe and installed it on a rotary table attachment for the milling machine. I used a regular end mill to cut the spline. After each cut, I rotated the shaft 45° and made the next cut. Eight cuts, and the spline was finished.

Here's a close-up of the splines. The shafts are ¼" round brass stock. The angle between faces of each cut is 90°. Some angles appear more acute, but this is an illusion caused by the camera angle. A square-end mill can cut only 90° angles.



Updated May 23, 2023