Total indicator reading

In metrology and the fields that it serves (such as manufacturing, machining, and engineering), total indicator reading (TIR), also known by the newer name full indicator movement (FIM), is the difference between the maximum and minimum measurements, that is, readings of an indicator, on the planar, cylindrical, or contoured surface of a part, showing its amount of deviation from flatness, roundness (circularity), cylindricity, concentricity with other cylindrical features, or similar conditions. The indicator traditionally would be a dial indicator; today dial-type and digital indicators coexist.