Gauge Block Interferometer

The GBI300 sets the standard throughout the World in Gauge Block Measurement by Interferometry. Many Primary Calibration Laboratories globally rely on NPL-Hexagon Gauge Block Interferometers for their Primary Calibration of Gauge Blocks. 

ISO 3650 and ASME B89.1.9-2002 (K & 00 Grades) and Federal GGG-G-15C Grade 0.5 (AAA) Gage Blocks up to 300mm (12") in length can all be calibrated to the most exacting Measurement Uncertainties available. Uncertainty values starting at 0.020 micrometers (< 1 micro inch) are attainable. 


  • Two frequency stabilised laser light sources 
  • Phase-stepping optical system for high precision length measurement and detailed analysis of Length Standard surface geometry
  • Large area interchangeable platens for optimum throughput 
  • Full and automatic measurement and compensation for ambient conditions 
  • Integrated and rapid Flatness and Variation in Length measurement
  • Automatic calculation of Length measurement results in metric or inch units
  • Flexible image processing software for the measurement of rectangular, square and round Length Standards
  • Hexagon offer Instrument calibration and a Platen refurbishment services if required
Measurement Capacity Gage Blocks up to 300 mm (12") length
Gage Block types Rectangular, Square and Round Gages made from Steel, Ceramic, Tungsten Carbide, Chrome Carbide etc
Length Measurement Uncertainty A Measurement Uncertainty of ± √ [17.32 + (263 x L)2 ] nanometres (“L” in meters) is possible  when the GBI300 is located within the correct environment
 Features measured Gauge Length, Flatness, and Variation in Length, of the Length Standard
 Measurement Results Displayed in Metric or Inch as appropriate
 Software FLaP for Windows™ validated by NPL for precision of computation