Machinists working strictly in metalworking shops don’t have many occasions to gage the thickness of soft materials. But many of our readers work in supporting roles, helping to build or maintain the machines that produce textiles, plastic films, paper, and other products that are compressible. Even readers who work only with metals should realize they’re not alone in their concern for accuracy; the shirt on your back, the newspaper you read this morning, and the garbage bag you tossed it into were all produced to exacting thickness tolerances.

Differences in gaging pressure readily translate into differences in the degree to which the sensitive contact compresses or penetrates the material being gaged. It’s therefore essential to use a standardized method when measuring the thickness of compressible materials.

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