This Resource Centre provides general guidance only. Always follow the equipment manufacturer’s instructions, the product technical data sheet and your site’s safe system of work. Isolate stored energy before maintenance. For safety-critical, regulated or uncertain applications, ask a competent engineer or the product manufacturer to confirm the specification.
Choose the right tool
A steel rule is useful for approximate length, a calliper for general dimensions and a micrometer for closer control. Bore gauges, thread gauges, feeler gauges and surface equipment solve different problems. Do not quote more precision than the tool and method can support.
Prepare the measurement
- Clean the part and measuring faces.
- Allow hot or cold parts to approach the reference temperature where accuracy matters.
- Check the instrument for damage and zero.
- Support the part without distortion.
- Measure away from burrs and worn edges.
Repeat and compare
Measure at more than one position to reveal taper, ovality or uneven wear. Record the unit, tool, location and result. When checking a fit, measure both mating parts.
Calibration and care
Store instruments clean and protected. Follow the organisation’s calibration system and quarantine equipment that has been dropped, damaged or gives doubtful readings.
Need help sourcing the item?
Send the manufacturer, reference, photographs and operating details.