Use to sharpen mower blades for Mammotion robot mowers (Luba and Yuka models). 

Loosen the screw an insert a worn blade, and then tighten the screw lightly. Sharpen the blade using a flat sharpening stone, and put slight pressure at the front of the guide. Both sides can be sharpened without loosening the screw. Works for left- and right-handed persons ;-)

The guide is designed with a fifteen degree angle. A M5x10mm screw + inset is used in this design, and the step file is attached if you want to change something.

I printed in ABS, but other materials should work fine as well. I printed really slow to get fine details around the front end of the guide. The 3MF file is also attached.

//Henrik