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M/T Mainshaft Inspection

  1. Inspect the gear surface and bearing surface for wear and damage, then measure the mainshaft at points A, B, C, D and E. If any part of the mainshaft is less than the service limit (except E), replace it with a new one.
    Standard:
    A (Ball bearing contact area):
    25.987−26.000 mm (1.0231−1.0236 in.)
    B (Distance collar contact area):
    28.992−29.005 mm (1.1414−1.1419 in.)
    C (Needle bearing contact area):
    34.984−35.000 mm (1.3773−1.3780 in.)
    D (Ball bearing contact area):
    25.977−25.990 mm (1.0227−1.0232 in.)
    E (Pilot bearing contact area):
    14.870−14.890 mm (0.5854−0.5862 in.)
    Service Limit:
    A:
    25.93 mm (1.020 in.)
    B:
    28.93 mm (1.139 in.)
    C:
    34.93 mm (1.375 in.)
    D:
    25.92 mm (1.020 in.)



  1. Inspect the runout by supporting both ends of the mainshaft. Rotate the mainshaft two complete revolutions when measuring the runout. If the runout is more than the service limit, replace the mainshaft with a new one.
    Standard:
    0.02 mm (0.001 in.) max.
    Service Limit:
    0.05 mm (0.002 in.)