Spi 19-418-3 Class Zz Minus Plug Pin Gage 0.418 in

Product Description

The SPI 19-418-3 is a Class ZZ minus plug pin gage with a nominal diameter of 0.418 inches, manufactured from steel. Plug pin gages are precision inspection tools used to verify that a drilled, reamed, or bored hole falls within a specified dimensional tolerance. The Class ZZ designation indicates a commercial-grade tolerance level suited for general shop-floor inspection work. This gage is ground to a minus tolerance of 0.0002 inches below the nominal size, meaning it checks the low-limit boundary of a hole. Machinists, quality technicians, and toolroom professionals use these gages as part of go/no-go inspection routines.

This plug gage is appropriate for inspection of machined components in manufacturing, fabrication, and toolroom environments where hole diameter conformance must be verified. The 0.418-inch size fits applications requiring close-tolerance bore verification in both production and maintenance settings. The steel construction holds up to regular handling in shop conditions. It is suited for use as a standalone check gage or as part of a broader set of pin gages organized by size for systematic hole inspection.

Key Features

• Class ZZ tolerance grade for commercial-grade shop inspection use
• Minus configuration checks the low-limit boundary of a 0.418-inch hole
• Tolerance of 0.0002 inches for consistent, repeatable measurement
• Steel construction for durability under routine shop handling
• Compact, single-piece form factor for easy storage and use in a pin gage set

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any inspection application requiring a Class ZZ minus pin gage at 0.418 inches nominal diameter.

Installation Notes

Plug pin gages should be handled with clean, dry hands or cotton gloves to prevent corrosion from skin oils. Before use, verify the gage and workpiece bore are at the same ambient temperature to avoid thermal expansion errors. Do not force a plug gage into an undersize hole, as this can damage the gage surface and introduce measurement error. Store in a protective case away from other metal tooling to prevent nicking the precision-ground surface.