Spi 19-428-2 Class Zz Minus Plug Pin Gage 0.428 in

Product Description

The SPI 19-428-2 is a Class ZZ minus plug pin gage machined to a nominal diameter of 0.428 inches with a minus tolerance of 0.0002 inches. Plug pin gages are precision go/no-go measurement tools used to verify bore and hole diameters to tight dimensional tolerances. This gage is constructed from steel for durability and dimensional stability under repeated use. Class ZZ designates the tolerance grade as defined by ASME B89.1.5, making this gage appropriate for inspection, quality control, and production verification tasks. Machinists, toolroom technicians, and quality assurance personnel are the primary users.

This gage is suited for shop-floor and inspection room use where hole diameter verification is required on machined parts, castings, or fabricated components. The 0.428-inch nominal diameter covers a common bore size encountered in general metalworking, tooling, and light manufacturing applications. The minus configuration means the gage diameter falls below the nominal, which is the standard practice for go-gage applications checking minimum acceptable hole size. Single-piece packaging makes it easy to add to an existing gage set or replace a worn member.

Key Features

• Class ZZ tolerance grade per ASME B89.1.5 for general-purpose inspection use
• Minus tolerance configuration — gage diameter is nominal minus 0.0002 inches
• 0.428-inch nominal diameter for common bore verification applications
• Steel construction for wear resistance and long service life
• Single-piece unit — no additional components required

Compatibility

Designed as a standard Class ZZ minus plug pin gage suitable for use with conventional gage handle holders sized for the 0.428-inch diameter range in general metalworking and inspection applications.

Installation Notes

Plug pin gages are handled and used by machinists and quality control technicians — no power tools or utilities need to be shut off prior to use. Clean the gage and the bore being measured before use to prevent debris from affecting readings or causing surface damage. Store the gage in a protective case away from other metal tools to prevent contact damage to the precision-ground surface. Apply a light coat of rust-preventive oil when storing to maintain the steel surface.