Folding Rack-and-Pinion Knife
Joerg Sprave is known for his inventive slingshot designs. He’s also into unique weapons. In this video, he shows off a neat custom knife he built with a rack-and-pinion mechanism. It pops open and closes quickly with the flick of a lever. He’s sending the prototype to a professional knifemaker to see if it can be refined and put into production.