Spur and helical gearing shall be used for all motions of steel plant overhead crane.  High speed reduction shall be through helical gears.  All pinions shall be integral with the shaft.  All gears shall be of hardened and tempered alloy or carbon steel with machine cut teeth. Gear teeth shall be preferably be cut in metric module system.  Surface hardening of teeth is not permissible.  Overhung gears shall not be used.

All gears shall be completely covered or guarded by covers firmly attached to brackets.  All gears shall be enclosed in oil tight casings.  All gear shafts shall be supported on bearings mounted in gear box. Splash lubrication system may be adopted for horizontal gear box & forced lubrication for vertical gear boxes of more than two stages.

Proper sealing shall be provided for prevention of leakage. All oil seals should be spring loaded viton type.

Gear boxes shall be of cast steel or fabricated and split each shaft centre line.  Fabricated gear boxes shall be stress relieved before machining.  For trolley travel motion, gear boxes with “T” split may be used.  The gear boxes shall be provided with breather vents, oil level indicator, dip stick and easily accessible drain plugs as per standard.  Radial clearance between gear box inner surface and the outside diameter of the gear shall be at least 11 times the depth of the largest gear tooth inside the gear box or 20 mm whichever in higher.  The facial clearance between inner surface of the gear box and the face of the gear or opinion shall be at least 20 mm.

The internal surface of gear box shall be painted with oil resistant paint.