This is the one I 3D printed (just the black bits) There is also some aluminium tube, some super magnets, a few bolts, and cheap AliExpress sharpening stones (320,800,2000,3000,5000,6000,8000,10000 and leather ones with polishing compound)
Super easy to use, just get the printed angle guide for the angle you want (currently it is set to 20 degrees) then go through the stones, any time you feel a burr on the underneath turn the knife over. If you've turned it over twice, change the stone for a higher grade. I double-check with my bench microscope to make sure I have at least removed any nicks or chips from the edge, also to see when I have removed all the sharpening scratches (when using the 10000 stone).