Spi 29-257-3 Class Zz Plus Plug Gage 0.257 in

Product Description

The SPI 29-257-3 is a Class ZZ Plus plug gage designed for go/no-go dimensional inspection of bored holes, drilled passages, and machined features requiring precise diameter verification. Built from steel, this gage checks a nominal diameter of 0.257 inches with a tolerance of 0.0002 inches, meeting Class ZZ Plus accuracy standards suitable for production floor and quality-control applications. Machinists, tool-and-die makers, and quality technicians use plug gages like this one to confirm that finished holes fall within acceptable dimensional limits before assembly or further machining operations proceed.

This gage is suited for use in manufacturing, fabrication, and precision machining environments where consistent hole-size verification is required. It applies to inspection of through-holes and blind holes in metal, plastic, and composite workpieces. The 0.257-inch nominal diameter makes it a direct fit for production lines producing parts with that specific hole specification. It is commonly used in job shops, aerospace component manufacturing, automotive part production, and general metalworking facilities where dimensional conformance is documented and traceable.

Key Features

• Class ZZ Plus accuracy rating for production-grade dimensional inspection
• 0.257-inch nominal measurement diameter for precise hole verification
• 0.0002-inch tolerance for tight conformance to dimensional standards
• Steel construction for durability and wear resistance in shop environments
• Compact form factor suitable for hand-held use at the machine or inspection station

Compatibility

Designed as an OEM-style inspection tool for use wherever a Class ZZ Plus plug gage at 0.257-inch nominal diameter is specified in a quality control or production inspection process.

Installation Notes

Plug gages are handled and used by quality technicians and machinists and do not require installation in the traditional sense. Store the gage in its protective case when not in use to prevent damage to the precision-ground surfaces. Clean the gage and the part bore before each measurement to remove chips, coolant, and debris that could affect readings. Do not force the gage into a hole; if resistance is felt, the bore is undersize and the gage should be withdrawn without applying lateral pressure.