The Fowler 81-piece rectangular steel gage block set provides an extensive selection of standard inch sizes from 0.050" through 4.000", allowing users to build a wide variety of precision reference dimensions for checking measuring instruments, setting comparative gages and performing dimensional inspection.

The hardened high-carbon/chrome steel blocks are stress relieved, precision lapped and mirror polished, and every set includes a fitted protective case and a Certificate of Inspection traceable to NIST.

Choosing a Grade

Economy / Workshop is the value-oriented choice for machine shops and production floors that need a comprehensive inch set without laboratory-grade accuracy, at ±0.000050".

AS-1 steps up to inspection-grade accuracy with individually serialized blocks and a fitted wooden case, for professional dimensional inspection where traceability per block matters.

Grade 0 is the tightest of the three, individually inspected for size, parallelism and flatness, for precision inspection, quality-control and calibration applications.

All three are the same 81-piece configuration covering the same size range — the choice is purely how tight an accuracy grade the work requires.

Calibration and Traceability

Gage blocks are the reference standards other instruments are set against, so their own calibration status governs the credibility of everything measured with them. WESTport provides ISO/IEC 17025 accredited calibration to keep a set documented and controlled over its working life.

Applications

Instrument setting and verification, comparative gage setting, dimensional inspection and layout in machine shops, manufacturing quality departments and calibration laboratories.