Spi 29-440-5 Class Zz Plus Plug Gage 0.44 in Steel

Product Description

The SPI 29-440-5 is a Class ZZ Plus plug gage used to verify the dimensional accuracy of drilled, reamed, or bored holes to a nominal diameter of 0.44 inches. Built from steel, this go/no-go style gage provides a tolerance of 0.0002 inches, meeting Class ZZ Plus precision standards for in-process and receiving inspection work. It is a standard hand tool for machinists, tool-and-die makers, and quality control technicians working in manufacturing, fabrication, and precision machining environments. The compact size and low weight of 0.2 pounds make it easy to carry and use at the machine or on the inspection bench.

This plug gage is suited for verifying hole sizes in production runs where consistent dimensional control is required. It is used in machine shops, fabrication facilities, and quality inspection departments handling steel, aluminum, and other machinable materials. The 0.44-inch nominal diameter covers a common bore size found in mechanical assemblies, jigs, and fixtures. Inspection professionals use gages in this class when tighter-tolerance classes such as X or XX are not required but consistent, repeatable measurement is still critical.

Key Features

• Nominal measurement diameter of 0.44 inches for precise hole verification
• Class ZZ Plus tolerance of 0.0002 inches for reliable go/no-go inspection
• Steel construction for durability and wear resistance in shop environments
• Lightweight at 0.2 pounds for easy single-hand use during inspection
• Compact design suitable for bench inspection or point-of-operation checking

Compatibility

Designed as an OEM-style precision measurement tool for use in standard plug gage handles and holders accepting 0.44-inch diameter Class ZZ Plus gaging members.

Installation Notes

Plug gages are handled and used by qualified machinists or quality control technicians. Before use, clean both the gage and the bore being measured to remove chips, coolant, and debris that could affect readings. Do not force the gage into a bore; apply only light, controlled hand pressure to avoid damaging the gage or the workpiece. Store the gage in a protective case or sleeve when not in use to prevent surface damage and maintain calibration integrity.