This gadget converts your rotary tool (i.e. Dremel) to a handy router. The inner thread of this gadget is compatible with most Dremel-like tools. The height can be adjusted by turning the knob part. The thread pitch of the adjustable mechanism is 2 mm so each half a turn lifts the tool 1 mm. Total movement of the lift is around 20 mm depending the machine is used. I've tested the gadget with Bosch GRO 10,8 v.
See an example groove cut on Youtube:
Threads of the adjustment ring has designed tight that it wouldn't have any backlash. At the very beginning the adjustment ring didn't run smoothly but after a while when all the excess print material was worn out it starts to work properly. I also applied a bit of silicon spray to the threads to lubricate the adjustment system.
The gadget is designed by using Vertex G4 software.