The advantages of using Geared Coupling on all directly connected machinery is now recognized and appreciated by engineers and operating men. Gear couplings are intended to compensate for the usual and unavoidable errors in alignment and should allow free lateral flowto the connected shafts. Even when favourable conditions permit perfect alignment to the two Shafts, there is no assurance they will remain so, the vibrations, the sinking of foundation, wear of bearings and inaccuracies in machining are all common enemies to the safe and efficient operation of connected machinery.