What is a 'soft foot' and how do you correct it?

What is a 'soft foot' and how do you correct it?

• A. An uneven mounting surface causing misalignment.
• B. A soft footing that does not affect alignment.
• C. A lubricant used on mounting feet.
• D. An uneven mounting surface causing misalignment; correct by shimming or leveling the machine feet.

Answer: (D)

Soft foot happens when the machine’s base doesn’t sit flat on its mounting surface—one or more feet are not in full contact. As soon as you bolt the machine down, those gaps let the frame distort, and the alignment you set can change or be lost when the machine is clamped. To fix it, find which feet aren’t contacting the surface, often with a straightedge and feeler gauges, and add shims under the low spots or adjust the leveling feet until all feet are solidly contacting the surface. Then re-torque the mounting bolts in a criss-cross pattern to avoid introducing stress, and recheck the alignment with appropriate gauges or indicators. This ensures the machine sits true and stays aligned when under load.

Soft foot happens when the machine’s base doesn’t sit flat on its mounting surface—one or more feet are not in full contact. As soon as you bolt the machine down, those gaps let the frame distort, and the alignment you set can change or be lost when the machine is clamped. To fix it, find which feet aren’t contacting the surface, often with a straightedge and feeler gauges, and add shims under the low spots or adjust the leveling feet until all feet are solidly contacting the surface. Then re-torque the mounting bolts in a criss-cross pattern to avoid introducing stress, and recheck the alignment with appropriate gauges or indicators. This ensures the machine sits true and stays aligned when under load.