BR549
I really like your screen name!
I completely understand what you're suggesting. Actually, I've considered doing exactly that. But, and there's always a but isn't there. Some of the tools I use are very small. I'm not confident that the smallest ones would completely block an optical beam. I mean, I'm talking .005" with a tiny depth of cut. For the same reason, I don't really want to come down on top of a touch plate either. They're kind of pricey and the tiniest corners of the bits can break and ruin the cut.
As for the tool holders, I don't really have any holders. The spindle just uses an air powered draw bar attached to the actual collet. My tools, all with 1/8" shanks, are dropped off and picked up by the shanks. Just the collet and the tools, no holders necessary.
In typing this, I realize that if my tool won't block a light sitting still, it might not block it while moving through it either. I guess I need to take a closer look at the optical switches and their specs. I currently use them for homing, and they are extremely accurate. Much more so than mechanical switches. I currently use the Optek OPB941W51Z for the home switches. They do offer a wider version, and the sensor aperture is only .010", so it just might work. It typically only requires about 40 to 50% of the light to be blocked for activation.
I would still like to learn how to turn a flag on and off though if possible. I think it could come in pretty handy at some time or another.
Royce