Endfloat in a drive system refers to which type of movement?

• A. Radial runout
• B. Angular misalignment
• C. Lateral deflection
• D. Axial play between connected shafts

Answer: (D)

Endfloat refers to movement along the axis of the shaft—the small amount of axial play between connected components such as gears, pulleys, and bearings. This is the lengthwise movement that occurs because of clearance and the need for some endplay to prevent binding during operation. It’s not about motion perpendicular to the shaft (radial runout), nor about a tilt between shaft axes (angular misalignment), nor about sideways bending (lateral deflection). Keeping endfloat within specification helps maintain proper gear meshing, preload on bearings, and overall smooth operation, and it’s usually controlled with spacers, shims, thrust washers, or by adjusting bearing preload.