Spi 19-851-5 Class Zz Minus Plug Pin Gage 0.851 in

Product Description

The SPI 19-851-5 is a Class ZZ minus plug pin gage designed for checking hole diameters to a nominal size of 0.851 inches. Built from steel, this gage is manufactured to a minus tolerance of 0.0002 inches, conforming to Class ZZ standards for go/no-go inspection work. It is used to verify that drilled, reamed, or bored holes fall within acceptable dimensional limits. Machinists, quality control inspectors, and tool-and-die professionals use plug gages like this one as a fast, reliable method for in-process and final inspection without the need for indicating instruments.

This gage is suited for dimensional inspection in machine shops, manufacturing facilities, and production environments where hole size verification is a routine part of quality control. The 0.851-inch diameter and Class ZZ tolerance class make it appropriate for general-purpose inspection applications where high-precision Class Z or ZZ-plus gages are not required. It is typically used as a go member in a matched gage set or as a standalone check for a single nominal hole size.

Key Features

• Class ZZ minus tolerance classification for general-purpose hole inspection
• Nominal diameter of 0.851 inches with a tolerance of 0.0002 inches
• Steel construction for durability and resistance to wear during repeated use
• Compact and lightweight at 0.2 pounds for easy single-hand operation
• Single-piece package quantity suitable for individual replacement or toolbox stocking

Compatibility

Designed as an OEM-style replacement or direct addition for Class ZZ plug gage sets requiring a 0.851-inch diameter member, compatible with standard gage handle systems that accept pin-style gage blanks of this diameter range.

Installation Notes

Plug pin gages are installed and used by machinists and quality control inspectors following standard metrology practices. Before use, clean the gage and the hole being checked to remove chips, coolant, and debris that could affect the reading. Handle the gage carefully to avoid dropping or striking it against hard surfaces, as impact damage can alter the ground diameter and void its calibration. Store in a protective case when not in use and periodically verify against a calibrated master to confirm ongoing accuracy.