I've tried at least 4 different extruders and all have been unreliable. This very clever design solves many of the slipping and skipping problems that have plagued the other extruders. I made slight modifications to allow 3mm filament and it works great! I did not use the lighter flint wheel, but instead used a mk8 gear that I already owned. I will post a remix when I get a chance. Thanks for posting this great design!