Gear couplings are used to couple two Shafts. Advantage of gear coupling over rigid flange coupling being that ò a slight misalignment is permissible between the two shafts. ò considerable reduction in the jerks as compared to those, which exists in Flange coupling. ò longer life gear for pinion gearbox and reduction gearbox gears are manufactured in grades en9, En19, en24 as per design requirement.