. Economical . Convenient . Reaches every contour easily . Gravity compensated The Tinsley Thickness Gauge is designed for measuring the dry-film thickness of any nonmagnetic material such as paint, plastic, etc., or plating such as zinc or chromium over a ferrous base (iron or steel). The thickness gauge consists of a special lightweight magnet attached to a spring and contained within a pencil-like tube. To take a measurement, the exploring head or magnet is placed on the surface and the body of the gauge is drawn away, thus extending the spring. The spring extension, the amount of which is observed on the scale, is proportional to the force required to detach the magnet from the surface. The reading is taken when the magnet breaks away from the surface, and the thickness is read directly from the scale. The standard scale for nonmagnetic coatings on mild steel also applies to coatings on cast iron and low-alloy steels, without appreciable error, and to coatings on high-alloy steels, with a small correction for thicknesses of less than 0.001 in. (0.025 mm). When used on bases other than mild steel, the gauge will still give repeatable results. For accurate work, a separate calibration is advised for each particular application. This can normally be carried out by the customer and a correction chart made.