I was just trying to point out to Mark that he will need some type of brake or "pawl" to position and lock the tool post. I included some pictures of mine for some ideas as he is building one from scratch.

I never said that you had to rotate it 300 degrees to lock the tool, just that you had to back the tool a little bit to lock it in after you rotated it. I did mention that my tool changer has a micro switch that activates once every rotation, but I don't know what exactly Prolight used this for.

Your right my tool changer does look a lot like the Dyna Mite one, but I have had this one torn completely apart and there there is nothing else inside that would allow it to unlock and turn back wards and there aren't any extra wires running out of the unit other than for the stepper motor and limit switch. The pawl is just a piece of metal and a spring.

Looking at this picture it looks like the Dyna Mite tool changer has a large solenoid on top to activate the pawl which is different than mine.

Dale P.