We previously went over our glossary of alignment terms with, “What is Alignment? Check out our Glossary of Alignment Terminology from A-H!” and later with Alignment Terminology from I-R. 

In the world of alignment, there is a multitude of technical terms. We provide definitions for some of these terms that you might hear from an engineer or technician as well as read in reports and might need further clarification. We welcome you to check out our glossary of terms S-Z relating to alignment, and hope you find it valuable!

SOFT FOOT – A term used to describe any condition where tightening or loosening the bolt(s) of a single foot distorts the machine frame. Must be corrected prior to final alignment.

SPACERS – A generic term for any coupling characterized by two flex planes separated by a connecting shaft without bearings or other supports between the flex points.

SQUISHY FOOT – A type of soft foot characterized by material (could be shims, paint, rust, grease, oil, dirt, etc.) acting like a spring between the underside of the machine foot and the baseplate contact area.

STAT – A short form of “stationary machine”. The stationary machine’s centerline is used as the reference line to measure the misalignment of MTBM (Machine To Be Moved).

STEP SHIM – Use of several shims to fill the wedge-shaped gap of a bent foot. Each shim is inserted to a different depth so that a stair-step-shaped support is built to better support the entire foot. All of the steps together are called a step shim.

THERMAL GROWTH – Movement of shaft centerlines associated with (or due to) a change in machinery temperature between the static and operating condition.

Thermal growth on pump motor set

TOLERANCE – The maximum permissible deviation from a specified alignment position, defining the limits of offset and angularity.

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by Ana Maria Delgado, CRL