Gage Blocks & Standards
Gage Blocks & Standards
Gage blocks, also known as gauge blocks, slip gauges, or Johansson gauges, are precision-ground and lapped metal or ceramic blocks used as dimensional reference standards in measurement and calibration. Manufactured to extremely tight tolerances — Grade K, Grade 0, Grade 1, and Grade 2 per ANSI/ASME B89.1.9 and ISO 3650 — they can be wrung together using molecular adhesion to form highly accurate composite lengths. Gage blocks serve as the primary dimensional traceability link between national measurement standards and workshop instruments.
Beyond standard rectangular gage blocks, this category includes setting masters for bore gauges, ring gauges, plug gauges, and step gauges used to calibrate and set a wide range of precision measuring instruments. Steel and tungsten carbide blocks are the most common materials; ceramic blocks offer excellent thermal stability and surface hardness. Gage block sets are essential in ISO 17025-accredited calibration laboratories, precision manufacturing, and aerospace and defense inspection departments.
Typical Applications
- Calibrating micrometers, calipers, dial indicators, and comparators in metrology laboratories
- Setting bore gauges, snap gauges, and fixed-limit gauges to specific reference dimensions
- Verifying CNC machine tool offsets and touch-probe calibration in manufacturing
- Establishing dimensional traceability for ISO 17025-accredited calibration laboratories
- R&D dimensional reference for prototype and tooling verification
Popular Brands
Starrett and Mitutoyo are the leading suppliers of gage block sets for industrial and laboratory use. Mitutoyo's ceramic and steel block sets are widely used for their surface finish and long-term stability. Starrett's setting masters are trusted in North American tool rooms. Mahr (Germany) and Tesa (Switzerland) are prominent in the European market, while Fowler offers competitively priced sets for general-purpose calibration work.
