TIR
Glossary · Tolerance & Measurement
At a glance
- Category /
- Tolerance & Measurement
- Also called /
- total indicator reading, full indicator movement, FIM
- Related /
- 2 terms
- Source /
- Written in the shop
TIR stands for total indicator reading — the full span between the highest and lowest values an indicator shows across a measurement.
Also called: total indicator reading · full indicator movement · FIM
In practice
TIR is a reading, not a characteristic: it is how runout, concentricity and similar conditions get measured in practice. "0.002" TIR" means the needle swept two thou from lowest to highest.
Why it matters
TIR is a total, not a plus/minus. Reading 0.002" TIR as ±0.002" doubles the allowed error and will pass parts that should have been rejected.
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