This is an automatic tool changer I designed for my PM-940CNC. It should be fairly easy to modify for almost any machine, and I’ve designed three sizes (6, 10 and 18 station) which should cover the range of hobbyist machines. Run by a stepper driver with a simple homing switch, and actuated pneumatically to reach the spindle.
I’m hoping to get the first one built (for my machine) this winter, and start offering them for sale in the spring. At that point I’ll probably be looking for 3-5 beta testers who I would give a price break to.