A universal toolhead mounting system I designed for my Anet A8. It may fit on other printers with the same mounting mechanism.
It can be used to swap printer toolheads in seconds, I have the stock Anet extruder and a Proxxon milling tool for making PCBs at the moment, and it works great. The toolheads fit firmly into the holder, print quality is excellent, and it is easily strong enough for PCB milling.
You just need 62x82mm base plates with a thickness of 3mm for all toolheads. These can be equipped with mounts for bowden extruders, laser cutters, cnc spindles, and so on. Things mounted to the back plates must leave 3mm of free space on both sides. I have included the STL for a router holder, feel free to design your own toolheads. As soon as my laser arrives, I will upload one more.
The stock Anet A8 extruder needs a little modification to fit, cut out 3x3mm grooves as shown in the picture.
Print standing up as shown in the picture, with supports for the belt holders.
Printing in other positions will most likely change the dimensions, and the toolheads will not fit anymore.