True or False: Excessive shaft runout can be caused by poor surface finish.

The assertion that excessive shaft runout can be caused by poor surface finish is true. When a shaft has manufacturing imperfections or inadequate surface quality, it can lead to uneven contact and imbalance as it rotates. Poor surface finish can create inconsistencies in the diameter or flatness of the shaft, contributing to variations in runout, which is the distance the shaft deviates from the centerline as it rotates.

In practical terms, when a shaft rotates, any irregularities on its surface can prevent it from maintaining a consistent path. This leads to vibrations, increased wear, and can affect the overall performance and longevity of the machinery. To ensure optimal performance and reliability, achieving a proper surface finish during machining is crucial, as it directly impacts the shaft's operational characteristics, including runout.