Total Indicator Reading

Total Indicator Reading (TIR) measures roundness in relationship to a center line. TIR is expressed in total diametric deviation. Example: +/- .004 (0.10mm) deviation is defined as .008 (0.20mm) TIR.

TIR is the total lateral distance traveled by the indicator needle resting against the O.D. of a round part as the part is turned one full revolution.

total indicator reading

<- Circularity | Rubber Over-Molding->