Meyer Gage

The collection carries four Meyer Gage product families: Class Z Pin Gage Sets (inch and metric), Class Z Pin Gage Libraries, Class X Pin Gage Sets, and Class X Pin Gage Libraries. All are precision cylindrical pin gages which are hardened, ground, and lapped steel rods manufactured to exact diameters used for GO/NO-GO hole inspection, hole size and depth measurement, checking distances and locations between holes, and setting micrometers, snap gages, and other comparative measuring instruments. Meyer Gage, based in South Windsor, Connecticut, has been manufacturing pin gages in the USA since 1965 and is widely regarded as the industry benchmark for pin gage quality and value.

A pin gage is a precision-ground cylindrical rod manufactured to an exact nominal diameter within a defined tolerance class. To inspect a hole, the operator selects the pin corresponding to the maximum allowed hole size (the GO gage) and attempts to insert it if it passes through freely, the hole is at least that size. They then try the pin corresponding to the minimum allowed size (the NO-GO gage) if it does not enter the hole, the hole is not oversized. This two-step GO/NO-GO check gives an immediate, definitive accept/reject decision without requiring a numeric readout or skilled interpretation of a dial indicator. Pin gages are faster than bore gauges for go/no-go decisions, require no calibration of the measurement instrument itself, and are the dominant method for high-volume production hole inspection across machining, stamping, molding, and assembly operations.

The class designation defines how tightly each pin is manufactured to its nominal diameter. Class Z pins have a size deviation tolerance of ±0.0001" (±0.0025mm) and a roundness geometry of 0.00005" making them a highly accurate working standard for everyday production inspection, GO/NO-GO gauging, and instrument setting. Class X pins tighten the tolerance further to ±0.00004" (±0.001mm) with a roundness limit of 0.00002" and a 4 microinch Ra surface finish 2.5 times tighter than Class Z in the inch system. Class X is the right choice for critical inspection where tight product tolerances leave little room for gage error, for maximizing the usable GO/NO-GO tolerance limit by minimizing gage uncertainty, and for calibrating micrometers, calipers, and other measuring equipment where the gage pin itself serves as the reference standard. For general production inspection, Class Z delivers more than sufficient accuracy at a lower investment.

Both contain individual Meyer Gage Class Z or Class X pin gages, but they differ in coverage, organization, and physical configuration. Sets are packaged in compact plastic foam cases covering a defined size range for example, the Class Z M1P set covers 0.061" to 0.250" in 190 pins. Sets are the right choice when the inspection task is focused within a specific size band and portability or bench-top convenience is important. Libraries provide broader coverage across multiple ranges, organized in multi-drawer metal cabinets. The largest Class Z libraries cover ranges from 0.011" up to 1.000" across thousands of individual pins systematically filed by size for immediate retrieval. Libraries are the standard configuration for metrology labs, tool rooms, and inspection departments that need access to any hole size on demand without assembling multiple sets. Larger library configurations (L3, L35, L4, L45 and their metric equivalents) consist of two four-drawer metal cabinets.

The Class Z inch sets cover the following ranges, available in both plus (+) and minus (-) tolerance directions: 0.011"–0.060" (50 pins), 0.011"–0.250" (240 pins combined range), 0.061"–0.250" (190 pins), 0.251"–0.500" (250 pins), 0.501"–0.625" (125 pins), 0.626"–0.750" (125 pins), 0.751"–0.832" (82 pins), 0.833"–0.916" (84 pins), and 0.917"–1.000" (84 pins). Half-thousand (.05) step variants are also available for each range. Metric Class Z sets are available in parallel coverage for millimeter-based quality systems. This systematic coverage ensures a pin is available in every 0.001" increment across the full range from 0.011" to 1.000".

All Meyer Gage Class Z and Class X pin gages are manufactured from 52100 bearing-quality carbon chrome alloy steel which is the same grade used in precision bearing manufacture for its dimensional stability, grindability, and resistance to wear. Each pin is heat treated and through-hardened to 60–62 Rockwell C, making it resistant to surface damage from normal inspection use and ensuring dimensional stability over a long service life. The surface finish is 8 microinch Ra or better on Class Z pins, and 4 microinch Ra or better on Class X pins both well above the finish quality required for accurate, repeatable contact gaging. All standard pins are 2 inches long with no sharp edges. Pins over 0.060" carry a laser-etched size, tolerance direction, and serial number directly on the pin for traceability to a specific unit and not just a box or set.

NIST traceability means each Meyer Gage pin gage can be related through an unbroken chain of calibrations to the national definition of the inch or millimetre maintained by the National Institute of Standards and Technology. Every Class Z and Class X set and library ships with a Certificate of Class Conformance (or Certificate of Accuracy for Class X) documenting this traceability. In regulated manufacturing environments operating under ISO 9001, IATF 16949, AS9100, or ISO 13485, all measurement standards used in production inspection must be traceable using pin gages without valid, documented traceability creates an audit nonconformance and potentially invalidates every GO/NO-GO inspection performed with those pins. Meyer Gage's ISO 9001–certified manufacturing and A2LA-accredited calibration laboratory provide the documentation infrastructure that quality systems require.

Tolerance direction indicates whether the pin's actual diameter is held above (plus) or below (minus) the nominal size. A plus-tolerance pin is manufactured slightly larger than nominal which is used as the GO gage, it ensures the hole is at minimum the specified diameter by passing through freely. A minus-tolerance pin is manufactured slightly smaller than nominal which is used as the NO-GO gage, it ensures the hole has not grown beyond the maximum allowed diameter by refusing to enter. For standard GO/NO-GO gaging you need both: a plus-tolerance pin at the minimum hole size specification (GO), and a minus-tolerance pin at the maximum hole size specification (NO-GO). Meyer Gage sets are sold separately in plus and minus directions, giving buyers flexibility to configure exactly the GO/NO-GO pair needed for a given hole tolerance without paying for pins outside the range of interest.

Meyer Gage Class Z and Class X pin gages are standard equipment in virtually every precision manufacturing and quality control environment where hole dimensions are a controlled feature. Primary applications include: GO/NO-GO inspection of drilled, reamed, bored, and punched holes in machined components; verification of hole location and center-to-center distance using pin pairs; measuring slot widths and groove diameters; setting inside micrometers, bore gauges, and snap gauges to a known reference dimension; and calibrating measuring instruments in lab and toolroom environments. Industries served span aerospace (fastener hole inspection, rivet hole sizing), automotive (engine and transmission bore inspection), medical device manufacturing (implant and instrument hole verification), electronics (connector and PCB hole gauging), and general precision machining and stamping.

All Meyer Gage orders ship free to the continental USA and are backed by a best-price guarantee. A 30-day return policy and Affirm financing at checkout are available. Government agencies and defense contractors operating under regulated quality systems can submit an RFQ through the dedicated Government RFQ page (DUNS: 13-715-2209, CAGE: 15F67). For help selecting the right class, size range, tolerance direction, set vs. library format, or inch vs. metric configuration for a specific inspection application, call or text Gustavo directly at 617-398-7852, Monday through Friday, 8am–5pm EST.