This is a simple hand-driven router plane for your chisel.

Print the 3 parts with standard settings (I have used a raw resolution, 0.28mm), but make the bottom body robust enough. The chisel handler is made for a small 6x6mm chisel, but there is enough clearance for designing other chisel handlers of bigger dimensions: let me know if you need other dimensions, however I have uploaded also the Blender source thus you can easily remix it.

BOM

Aside the printed parts you need;

+ a chisel :-) + 1 M4 screw with hex head (or put two M4 nuts into its head inside the thumb-wheel) long about 25/30mm; + 1 M4 nut to fit inside the chisel handler part.

Acknowledgements

The thumb-wheel design has been taken from https://www.thingiverse.com/thing:4328458