Spi 19-307-8 Class Zz Minus Plug Pin Gage 0.307 in

Product Description

The SPI 19-307-8 is a Class ZZ minus plug pin gage used to check and verify bore and hole diameters to a precise dimensional standard. This single-end pin gage measures 0.307 inches in diameter and is manufactured from steel for consistent hardness and wear resistance. The minus tolerance designation means the pin is ground to the lower boundary of the nominal size, allowing go/no-go gauging workflows where controlled undersize entry confirms acceptable bore geometry. Machinists, toolroom technicians, and quality control inspectors rely on Class ZZ gages for production-floor inspection of drilled, reamed, and bored holes.

This pin gage is suited for use in machine shops, manufacturing facilities, and toolrooms where hole diameter verification is part of a standard inspection process. It fits into standard gage handle sets and pin gage sets for organized storage and quick retrieval. The 0.307-inch size covers a common range of drilled and reamed hole sizes found in general metalworking and light manufacturing applications. Both production inspectors and setup technicians use this type of gage to confirm that holes fall within specification before assembly.

Key Features

• Class ZZ tolerance rating suitable for general-purpose production inspection
• Minus designation ground to the lower boundary of the 0.307-inch nominal diameter
• Tolerance of 0.0002 inches for reliable dimensional verification
• Steel construction provides durability and resistance to wear during repeated use
• Compatible with standard plug gage handles for ergonomic handling

Compatibility

Designed as a standard single-end plug pin gage for use with conventional pin gage handles and gage block sets used in general metalworking and quality inspection applications.

Installation Notes

Pin gages should be inserted and withdrawn from test holes by hand without forcing. Clean both the gage and the workpiece bore before gauging to prevent debris from affecting the measurement or damaging the gage surface. Store pin gages in a protective case or indexed tray to prevent surface damage that could compromise accuracy. Calibration against a traceable standard is recommended at regular intervals to maintain measurement integrity.