What is the most likely cause of excessive dial movement when torqueing down bolts after adding shims?

Excessive dial movement when torqueing down bolts after adding shims is most likely indicative of a soft foot condition. A soft foot occurs when one or more of the mounting feet of a machine do not make proper contact with the mounting surface, which can lead to uneven loading and, consequently, excessive dial movement as the tension is applied during the bolting process. In essence, when the torque is applied, the unevenness causes fluctuations in dial readings due to the insufficient support beneath the machinery.

Understanding this concept is crucial because addressing a soft foot condition typically involves identifying and correcting the unevenness in the machine's base or feet before proceeding with further adjustments or installations. This ensures a stable and secure setup, allowing for proper alignment and preventing future issues.