Can free hand rotation prove that a mounted bearing has the correct operating clearance?

LILY Bearing | 2026-10-28

Best answer

Understand what a room-temperature feel check actually shows

Hand rotation may reveal an obvious obstruction or unusual roughness, but it samples a limited condition.

It does not reproduce the operating load, speed, thermal distribution or lubricant behaviour. The operating-clearance framework includes effects that may be absent during that check, while a controlled test run examines the mounted assembly under a specified procedure. A smoothly turning bearing can therefore still have unresolved operating-clearance questions. Conversely, noticeable resistance may include seal and lubricant effects and does not by itself identify a clearance defect. Record what was observed without converting the subjective feel into an unstated measurement or engineering acceptance.

Keep the observation and the acceptance evidence separate

Use a repair sheet with one field for the hand-rotation observation and other fields for dimensional checks, applicable clearance verification and the authorised running test. “Turns smoothly before coupling” is a useful, bounded observation. “Clearance passed because it turns smoothly” is a conclusion that the observation does not support.

If the manufacturer's installation procedure requires a particular clearance measurement, record its method, conditions and result. If it requires a test run, record the relevant speed, load and trends. This separation helps the next technician understand which checks were actually completed and which aspects of the operating condition remain to be verified.