Two shafts connected by a sleeve coupling should be aligned in which directions?

• A. Both horizontally and vertically
• B. Only horizontally
• C. Only vertically
• D. Neither horizontally nor vertically

Answer: (D)

The main idea is that a sleeve coupling is a rigid, non-flexible connection. Because it does not allow any sliding or soften the misalignment between the two shafts, the shafts must be perfectly aligned so there is no misalignment in any plane. This means zero offset (horizontal or vertical) and zero angular misalignment; they should lie on the same straight centerline. If there’s even a small misalignment in either direction, the rigid sleeve imposes bending loads on the shafts and sleeve, leading to excessive wear, vibration, and potential failure. That’s why the correct approach is to align so there is no misalignment in both directions. In contrast, couplings designed to be flexible can tolerate some misalignment, but a sleeve coupling requires exact, zero misalignment.