Spi 19-256-7 Class Zz Minus Plug Pin Gage 0.256 in

Product Description

The SPI 19-256-7 is a Class ZZ minus plug pin gage designed to verify hole diameters to a nominal size of 0.256 inches. It is manufactured from steel and held to a tolerance of 0.0002 inches, making it suitable for go/no-go inspection work in production and maintenance environments. Class ZZ is the standard tolerance grade for general-purpose inspection of commercial-quality work. Machinists, quality technicians, and tool room personnel use this type of gage to confirm bore dimensions on machined components, castings, and fabricated parts.

This gage is used in machine shops, manufacturing facilities, and maintenance departments where precise hole verification is required. The minus designation means the gage is ground undersized relative to the nominal diameter, which is standard practice for go-type plug gages used to confirm minimum acceptable hole size. It is well suited for incoming inspection, in-process checks, and final verification of close-tolerance bored or drilled features.

Key Features

• Nominal diameter of 0.256 inches for direct hole size verification
• Class ZZ tolerance grade for general commercial inspection use
• Minus designation ground undersized to nominal for go-gage application
• Steel construction for durability and dimensional stability
• Tolerance of 0.0002 inches for reliable, repeatable measurement

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for general-purpose dimensional inspection of 0.256-inch nominal diameter holes in machined or fabricated components.

Installation Notes

Plug pin gages are handled and used by quality technicians and machinists. Before use, clean the gage and the hole being inspected to remove chips, coolant, and debris that could affect the reading. Apply light, consistent hand pressure when inserting the gage — never force it, as forcing can damage both the gage and the workpiece. Store the gage in its case or on a protected surface to prevent nicks and corrosion that would affect calibration.