National Physical Laboratory

Gauge blocks and length bars

Gauge block, length bar and step gauge calibration.

Gauge Blocks
Gauge blocks

NPL has the UK's most accurate calibration services for the measurement of engineering length standards.

Gauge blocks (slip gauges), length bars and step gauges are among the most common length standards used in engineering. They are used to calibrate or verify the performance of a wide range of instruments or other standards ranging from micrometers and verniers to Coordinate Measuring Machines. Before use, these standards must themselves be calibrated according to various national or international specification standards and should then be subject to an ongoing programme of re-calibration, according to the frequency of use and the required accuracy.

By offering the most accurate services in the UK, NPL can help you reduce your uncertainty, thereby improving process control, reliability and efficiency.

NPL offers a range of calibration services for gauge blocks, length bars and step gauges. We can calibrate: the central length, flatness and variation in length of gauge blocks and length bars, the inter-face spacing of step gauges; and the thermal expansion coefficient of long gauge blocks and length bars.

The majority of these services are accredited by UKAS and internationally recognised under the CIPM Mutual Recognition Arrangement.

Calibration service details:


Customer Service tel: +44 20 8943 8631

Last Updated: 18 Aug 2015
Created: 3 Sep 2009


Please note that the information will not be divulged to third parties, or used without your permission