Began work on the Vertical Stabilizer. Clecoed all the parts together then filed, sanded, rounded all edges. Primed the spar reinforcement plate. All holes were brought up to size as required. The skin and understructure were dimpled. Everything went well except the C-Frrame dimpler was giving me grief by coming apart when I hit. The dimple dies and head stock would fly out of the frame and hit the skin. Yes, it damaged it.