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Brake Drum

Brake Drum Specifications
DRUM DIAMETER 250 mm (9.84 in.)
DRUM DIAMETER (Maximum)
This marking includes 0.76 mm (0.030 inch) for allowable drum wear beyond the recommended 1.52 mm (0.060 inch) of drum refacing.
Cast/stamped into outside surface of drum
DIAMETER VARIATION (Maximum) 0.090 mm (0.004 in.)
DRUM RUNOUT (on lathe) 0.15 mm (0.006 in.)
INITIAL DRUM MACHINING CUTS
Initial machining cuts should be limited to 0.13 mm (0.005 in.) at a time as heavier feed rates can produce taper and surface variation.
0.13 mm (0.005 in.)
FINISH DRUM MACHINING CUTS 0.0254 mm (0.001 in.)