What is the primary concern when using the least number of shims to achieve correct stack thickness?

The primary concern when using the least number of shims to achieve correct stack thickness is to minimize the springing effect. The springing effect refers to the potential for flexible components or surfaces to move or flex under load, which can lead to misalignment and operational issues. By using fewer shims, one can maintain a more rigid connection, thus reducing the likelihood of unwanted movement during operation. This is crucial as excessive shimming can create gaps and introduce flexing, negatively impacting the machinery's performance and longevity. In this context, a stable stack ensures that the components remain correctly aligned and function efficiently under load, highlighting the significance of minimizing the springing effect in the design and assembly processes.