New Precision Tooling

On vertical mills, one useful tool is a rotary table which you use to turn parts some exact number of degrees.  In my case, think setting circles.  On a telescope mount these are marked in degrees of celestial latitude or declination.   The degrees of celestial longitude for largely historical reason are hours and minutes of Right Ascension.  

Setting circles are pretty well obsolete in the era of goto mounts but one nice aspect besides tradition is thst if you get your mount aligned on an object of known declination and RA you can lock the setting circles to the two axes and move the telescope to whatever declination and RA you want for another object.  Just keep the clock drive running. 

Making setting circles requires some precision in marking the lines.  In this case. I will put the rotsting table on a vertical support and write a program that loops through the degrees and RA hours and minutes moving the workpiece to position,  moving the finest carbide endmill I can find to the edge and cutting in a line and probably a number if I can find a small enough font that I can still read.

I could do this manually and this rotary table was originally manual but it only cost about $220 for Sherline to upgrade it to CNC 

The video shows it in action and the gCode telling to advance to 90 degrees position.  Once I figure out how to upload videos in the Blogger app.