Gears & Gear Coupling Gear Couplings are used to couple two shafts. Advantage of gear coupling over rigid flange coupling being that · A slight misalignment is permissible between the two shafts. · Considerable reduction in the jerks as compared to those, which exists in flange coupling. · Longer life Gear for pinion gearbox and reduction gearbox Gears are manufactured in grades En9, En19, En24 as per design requirement