Today I finally got around to making a ring engraved with Pi around the periphery.
The ring I machined (see the previous post on machining a stainless steel ring) had an outside diameter of .984", thus a circumference of 3.091". The text was laid out in the direction of the y-axis, for conversion to rotary coordinates by Bobcad. The width of the ring was .284"
This yielded 331 lines of G code that looked like this:
N160 G00 X0.1176 Z0.1 A328.7806
N170 G00 X0.1116 Z0.1 A326.9334
N180 G01 X0.1116 Z-0.0015 A326.9334
N190 G01 X0.1201 Z-0.0015 A323.8664
N200 G01 X0.1071 Z-0.0015 A320.4074
The 4th axis set up, with a diamond drag bit in the spindle.
Engraving the ring, .0015" deep.
Photographing the ring was hard, and I'm not happy with the results.
The "3" came out too angular as well - A axis moves cannot use arcs, only straight lines, and I oversimplified the curve to polyline conversion. Live and learn. We'll see if it sells on Etsy.