Planishing Hammer with Rotary Hammer-Drill as Hammering Mechanism

I fabricated this planishing hammer to use in my sculpture-making process. The rotary hammer-drill is secured to a hinged arm. The weight of the hammer-drill, plus the arm, holds it against the workpiece. I can adjust the speed with a router speed control to get a more aggressive effect, or a more polished finish. The throat depth is 36".