What Is the Difference Between a Spline Shaft and a Keyed Shaft?

Both spline shafts and keyed shafts are designed to transmit torque,but they differ in design and performance:
·A keyed shaft has a single slot(keyway)machined into it,into which a metal key is inserted to connect the shaft with a mating hub or gear.This design is simple but focuses the load on the key,which can be a weak point.
·A spline shaft,by contrast,has multiple teeth or grooves along its length,distributing torque evenly over a larger surface area.This results in better load capacity,improved alignment,and reduced wear.