It worked very well. I had that ring mounted on an aluminum plate mounted on two drawer slides. That was also driven by a stepper. So I had a linear and a rotary translation. A plate of optical filters under test was placed on top of the rotary ring and a light source on top was triggered when the table translated to each filter position. It was very simple. And very cheap. I built it in 2 weeks. I used turbocnc to drive it, using G code as a program to drive the sampler. That ran off a dumpster computer with a bad hard drive. I ran the whole thing off a floppy.
This amazed the company that had just hired me. They expected to spend $20K and several months to develop this -- they had a backlog of filter orders, and this automated testing to help them catch up. I think that with the controller (hobbyCNC kit) the total materials cost was about $250.
They made me engineering manager after that. A mistake I later had to correct.