Question

What is TIR? How is it measured?

Answer 1

TIR is simply the difference between the maximum and minimum values measured across an entire rotating surface about a reference axis.

the correct method to measure TIR on 2 ID's of a cylindrical part. From what I was taught and from what I believe is defined in ANSI Y-14.5, the correct way to measure the TIR on such a part is to place the part in a V-Block with an indicator on each ID and an indicator on the OD and measure the delta of the ID's while monitoring the OD.

Answer 2

TIR means total indixator reading also known by the newer name full indicator movement