Pitches include: SAE Rethread Files (Threads per inch): 9 1011 12 13 14 16 18 20 24 27 28 and 32 Metric Rethread File (Millimeters per thread): 0.75 1.00 1.25 1.50 1.75 2.00 2.50 3.00. Thread restorer files are used to help restore external threads. Just select the right threads per inch or millimeters by using regular file strokes.