Spi 19-439-9 Class Zz Minus Plug Pin Gage 0.439 in

Product Description

The SPI 19-439-9 is a Class ZZ minus plug pin gage manufactured from steel, designed to verify bore and hole diameters to a high degree of precision. With a nominal diameter of 0.439 inches and a tolerance of 0.0002 inches, this gage is used to confirm that a workpiece feature falls within specified dimensional limits. Class ZZ gages are the standard working-grade gages used on the shop floor for go/no-go inspection tasks. Machinists, quality control technicians, and tool room professionals use plug gages like this one as part of routine dimensional verification on machined components.

This pin gage is suited for use in precision machining environments, inspection departments, and production floor quality checks. It is appropriate for verifying drilled, reamed, or bored holes in metal, plastic, or composite workpieces where tight dimensional tolerances must be confirmed. The 0.439-inch nominal size fits common fractional and decimal-inch bore applications encountered in general metalworking, tool and die work, and precision fabrication. Individual gage pins are often used as part of a larger set or as standalone replacement pins for existing gage handles.

Key Features

• Class ZZ tolerance class — standard working grade for shop floor go/no-go inspection
• Minus designation — gage is ground to the minus side of the nominal diameter for go-gage applications
• Nominal diameter of 0.439 inches with a tolerance of 0.0002 inches
• Steel construction for durability and wear resistance in production environments
• Individual pin format — compatible with standard gage handle sets

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use with conventional gage handles and pin gage sets sized for 0.439-inch diameter pins.

Installation Notes

Plug pin gages should be handled with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Before use, inspect the gage surface for nicks, burrs, or wear that could affect measurement accuracy. When inserting the pin into a bore, apply light, consistent hand pressure only — never force the pin or use tools to drive it. Store pin gages in a protective case away from other metal tooling to prevent surface damage.