Lang Tools (2573) 3-Pc. Thread Restorer File Set restores damaged external threads, any diameter, left or right hand. Just select the proper number of threads per inch or millimeters per thread, and overlapping several good threads, work over the area using regular file strokes. These rethreading files are highly tempered for strength and durability and are packaged in a reusable pouch. Pitches include: SAE Rethread Files (Threads per inch): 9, 10, 11, 12, 13, 14, 16, 18, 20, 24, 27, 28, and 30, Metric Rethread file (Millimeters per thread): 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.50, and 3.00.