The Nicholson flat hand file for aluminum has a rectangular shape with double-cut American pattern Type A teeth on both sides for smoothing and shaping straight surfaces, and provides good chip clearance for a smooth finish when filing aluminum.
Used to extend threaded drill bits, pilot cutters, or any other cutter with a 1/4-28 thread. Has a 1/4" Hex Drive on the shank end to fit a drill or screwdriver, and a 1/4-28 internal (female) thread at the other. 10" extension length.