Spi 19-371-4 Class Zz Minus Plug Pin Gage 0.371 in

Product Description

The SPI 19-371-4 is a Class ZZ minus plug pin gage with a 0.371-inch nominal diameter, manufactured from steel for consistent dimensional accuracy in go/no-go inspection work. Class ZZ is the standard tolerance class for production gaging, and the minus designation means the gage is ground below nominal to the low side of the tolerance range. With a tolerance of 0.000200 inches (0.0002 inches), this gage is suited for checking hole sizes, bore diameters, and feature openings where controlled fit and dimensional conformance are required. Machinists, quality control technicians, and toolroom personnel use pin gages as part of standard inspection routines on the shop floor or in the inspection room.

This plug pin gage is used in production and toolroom environments to verify hole diameter acceptance on machined parts, castings, and fabricated components. It is typically used as part of a go/no-go gage set or as a standalone check gage for a specific feature dimension. Applications include bore inspection on machined housings, fixture verification, and quality control checks in general metalworking, aerospace, automotive, and manufacturing environments. The 0.371-inch diameter targets holes drilled or reamed to that nominal size.

Key Features

• Class ZZ tolerance class — standard grade for production and general inspection use
• Minus designation — ground to the low side of nominal for proper go-gage function
• 0.000200-inch tolerance for reliable dimensional verification
• Steel construction for durability in shop floor and inspection room environments
• 0.371-inch nominal diameter for direct hole size verification

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use in go/no-go inspection setups and toolroom applications requiring a 0.371-inch diameter check gage.

Installation Notes

Pin gages are handled and used by quality control technicians and machinists — no installation in the traditional sense is required. Store pin gages in their protective case when not in use to prevent surface damage that would affect accuracy. Handle with clean, dry hands or cotton gloves to prevent corrosion from skin oils. Verify gage condition and cleanliness before each use; a damaged or contaminated gage surface will produce unreliable inspection results.