I've built a "Rusty", was not impressed, slow, poor control and didn't hit hard. I wanted to build a Clay Spencer tire hammer, but every time he was having a build I was on the water overseas. I finally managed to find one for sale and snapped it up. A buddy of mine looked at mine and copied it and has been very happy with it. It uses a spare tire for the clutch, and basically a copy of the Dupont little giant linkage. I am pretty sure Clay has plans available now, but if you can get the pivot hole to pivot hole measurements from a 50 pound little giant you can figure everything else out.