Summary

One of the key for master sharpening is a perfect constant blade angle . This tool holds the knife at a preset perfect cutting angle during sharpening with a stone.
For Knife with blade width 1.5 cm to 6cm, thickness 1.5mm to 3mm
Default Sharpening angle 20 degree, i.e. 40 degree both sides.
You need a cheap 8 inches long ceramic or carbide sharpening stone. Tape one end to reduce friction.

Print :
PLA
Rotate 90 degree on its side to print
Speed 60
Shell 1.2mm, Fill 15%

Usage:
overhange the knife blade edge 1 to 2mm beyond the edge of the sharpener holder

This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/g4wrSqB3GS5