Spi 29-991-7 Class Zz Plus Plug Gage 0.991 in

Product Description

The SPI 29-991-7 is a Class ZZ Plus plug gage designed to verify that a bored, drilled, or reamed hole meets a precise dimensional requirement of 0.9910 inches in diameter. Manufactured from steel, this go/no-go style gage gives machinists and quality control technicians a fast, reliable method for checking hole size conformance on the shop floor or at the inspection bench. The tolerance on this gage is 0.0002 inches, consistent with Class ZZ Plus accuracy standards. At 0.2 pounds, it is a compact, hand-held instrument suited for repeated use in production and inspection environments.

This plug gage is used wherever precision hole verification is required. Typical applications include incoming inspection of machined components, in-process quality checks on milling or boring operations, and final inspection of parts produced to tight dimensional tolerances. It is a standard tool for machinists, tool and die makers, quality inspectors, and maintenance technicians working in metalworking, manufacturing, and industrial maintenance settings.

Key Features

• 0.9910 inch nominal diameter measurement for precise hole verification
• 0.0002 inch tolerance meets Class ZZ Plus accuracy requirements
• Steel construction for durability and dimensional stability under repeated use
• Compact and lightweight at 0.2 pounds for easy one-hand operation
• Single-piece package quantity supports individual tool crib or inspection kit stocking

Compatibility

Designed as a standard Class ZZ Plus plug gage for use in any inspection or production environment requiring hole diameter verification at 0.9910 inches nominal.

Installation Notes

Plug gages are precision instruments and should be handled carefully to prevent surface damage or calibration drift. Store in a protective case or dedicated tool holder when not in use, and avoid dropping or contacting the gage surface against hard materials. Clean the gage and the hole being measured before use to prevent debris from affecting readings. Periodic recalibration against a traceable standard is recommended to maintain measurement integrity.