Spi 19-374-8 Class Zz Minus Plug Pin Gage 0.374 in

Product Description

The SPI 19-374-8 is a Class ZZ minus plug pin gage with a 0.374-inch nominal diameter, manufactured from steel and held to a tolerance of 0.0002 inches. Plug pin gages are used to verify that a hole, bore, or opening meets a specified dimensional requirement — the part either passes or it does not. Class ZZ is the most common working-gage class, suited for general inspection of production parts where high-precision laboratory tolerances are not required. This gage is handled by machinists, quality technicians, and tool-room personnel performing in-process or final inspection work.

Class ZZ minus plug gages are used across general manufacturing, machine shops, fabrication facilities, and quality control departments. The minus designation means the gage is ground to the lower end of the tolerance band, making it appropriate for go-gage applications where confirming minimum acceptable hole size is the objective. This gage fits standard inspection workflows and is compatible with gage handle sets designed for the 0.374-inch diameter range.

Key Features

• Class ZZ tolerance class — suitable for general-purpose production inspection
• Minus designation for go-gage applications at the lower tolerance boundary
• 0.374-inch nominal diameter for direct hole and bore verification
• 0.0002-inch tolerance for consistent, repeatable measurement
• Steel construction for durability in shop and inspection environments

Compatibility

Designed as an OEM-style working gage for use with standard plug gage handles sized for the 0.374-inch diameter range in general machining and inspection applications.

Installation Notes

Plug pin gages should be handled by quality technicians or machinists familiar with ASME B89.1.5 gage handling and care standards. Clean and deburr the hole being inspected before use to avoid damage to the gage surface. Store the gage in a protective case away from other metal tools to prevent nicks or wear that would compromise measurement accuracy. Do not force the gage through a hole — if resistance is felt, the hole is undersize.