To minimize the springing effect from shims, what is the maximum number of shims that should be used?

Using a maximum of three shims is recommended to minimize the springing effect, which refers to the compliance or flexibility that can occur with multiple layers of shims. When shimming machinery or equipment, keeping the number of shims to a minimum enhances stability and reduces the risk of misalignment or excessive movement over time.

Each additional shim can introduce a point of articulation or flexibility that may lead to unwanted movement, particularly under load. Having three shims allows for sufficient adjustment capability to achieve level and proper alignment while maintaining a solid and stable foundation. Beyond this number, the risk of creating a more significant springing effect increases, potentially undermining the installation's integrity and performance.

In practice, the aim is to achieve a balance where enough shimming can compensate for gaps while avoiding excess that contributes to instability, making three the optimal choice in this scenario.