This tool is based on the Tracer Proscribe tool and is designed for use with the Tracer Deep Hole Pencil. It can be used as a profile marker, parallel scribing marker and also used in Compass mode.
I printed the parts in ABS.
You will also need the following parts:-
Screw Knob M5x40mm similar to the one in the image from Amazon
M5 screw - Cut the head off, then heat the screw and insert it into the Knurled Nut Handle
2 x M5 Nuts