Worked on adding the aileron balance weights. Removed the end of the aileron. Positioned the ribs that the balance weight arm bolts to. Cut opening in the front of the aileron where the balance weight arm goes through. Drilled holes in the skin and outer rib to rivet the rib. Locateed with clecos and temporarily mounted the balance weight arm. Located the opening in the rear spar where the balance weight arm passes through. Clecoed the aileron hinge to the rear spar so the aileron can be mounted to check location of the balance weight arm.