Recess TIR Gage

This gage was specifically developed to measure the concentricity of a screw’s shank to its recess or external drive system quickly and accurately. This fastener characteristic is becoming more critical with the widening use of automatic screw feeding and driving assembly equipment. If a screw’s recess is too far from the axis of its shank the automatic equipment’s driver can not engage the recess and the equipment will jam, ruining its efficiency. This gage’s single recess measuring element will inspect all styles of recesses in all screw sizes #4 through 1/4″ (M3M6).

The gage comes with an 11 piece collet set and an electronic indicator that provides .0001″ resolution and the absolute TIR measurement without adding or subtracting. This easy-to-use gage provides Gage Repeatability and Reproducibility Study results of less than 20%.

TIR vs total runout

Total Indicator Reading (TIR) and total runout are both measurements used to assess the accuracy of a round object, but they have distinct differences:

1. **Total Indicator Reading (TIR):** This is a measure of the variation in a surface as it rotates around a datum axis. TIR is the difference between the highest and lowest points recorded by a dial indicator as the object is rotated. It represents the maximum deviation of the surface from a perfect circle. TIR is often used to check the concentricity and roundness of cylindrical parts.

2. **Total Runout:** This is a more comprehensive measurement that includes both the roundness and the axial alignment of a surface. Total runout measures the combined effect of variations in the surface profile and any axial displacement or tilt as the part rotates. It is assessed along the entire length of the surface, providing a single value that reflects all geometric deviations, including circularity, straightness, and coaxiality errors.

In summary, TIR focuses solely on the roundness in a single plane, while total runout encompasses roundness along the entire length of the surface, including any axial misalignment.