Coating rolls used to apply the thinnest of coatings must be constructed to extremely tight tolerances. Today’s super thin web coatings require extremely tight tolerances from coating rollers. Roller tolerance (or concentricity) is measured as TIR – Total Indicated Runout. The tighter the tolerance, the smaller the TIR dimension. Since rolls are ground and polished with roll bearings in place, Webex uses special bearings with certified tolerances. Most coating rolls are also Webex ThermEx heat transfer rolls often specified with a chrome-plated finish. To ensure such exacting tolerances on coating rolls, the company uses an electronic gauge to measure roll TIR.