Tedious work, and slow going describes the process to countersink the R-916 rudder trailing edge. It is such a thin piece of metal, and has the angles that make it difficult to support as you work with it. I had used the hand counter-sink in the air-drill but would have preferred to use the drill press; however, that would have required a special base assembly to hold the work perpendicular to the drill in the drill-press -- which I didn't have. Afterwards, began deburring the right rudder skin prior to dimpling.
