How much excessive shaft runout on a coupling would be considered greater than the acceptable limit?

The acceptable limit for excessive shaft runout on a coupling is typically considered to be around 0.003 inches. At this level, the runout can start to impact the performance of the equipment, leading to issues such as increased wear, vibration, and potential failure of the components involved. Managing runout is crucial for ensuring proper alignment and operation of rotating machinery.

Shaft runout measurements above this threshold can significantly impair the coupling's functionality, resulting in mechanical problems that could escalate into more serious equipment failures. Regular monitoring and maintaining runout within acceptable limits are vital for optimal operational efficiency and longevity of machinery.