Spi 29-172-4 Class Zz Plus Plug Gage 0.172 Inch

Product Description

The SPI 29-172-4 is a Class ZZ Plus plug gage designed for precision bore and hole inspection in machining, manufacturing, and quality-control applications. Built to a diameter of 0.172 inches with a tolerance of 0.0002 inches, this gage provides a reliable go/no-go reference for verifying drilled, reamed, or bored features. The steel construction delivers the hardness and wear resistance required for repeated use on production floors and in inspection rooms. Metrology technicians, machinists, and quality control inspectors use plug gages like this one to confirm that finished workpieces meet dimensional print requirements before assembly or shipment.

This plug gage is suited for use in precision manufacturing environments where small-diameter bore verification is required. It is appropriate for both job-shop and high-volume production settings. Typical applications include checking hole diameters in machined components, tooling fixtures, and sub-assemblies. The 0.172-inch nominal size makes it appropriate for small-bore inspection tasks where standard micrometer or caliper measurement may not provide sufficient repeatability or access.

Key Features

• Class ZZ Plus tolerance class for reliable go/no-go inspection of small-diameter bores
• Nominal diameter of 0.172 inches for precise small-bore measurement
• Tolerance of 0.0002 inches ensures close dimensional control
• Steel construction for durability and long service life in production environments
• Compact single-piece form suitable for hand inspection use

Compatibility

Designed as a standard Class ZZ Plus plug gage for inspection of 0.172-inch nominal diameter holes and bores in machined components across general manufacturing and metrology applications.

Installation Notes

Plug gages should be handled and stored according to standard metrology practices to prevent surface damage that could affect accuracy. Clean the gage and the bore being measured before use to remove chips, coolant, and debris. Gages should be periodically recalibrated against certified reference standards in accordance with applicable quality system requirements such as ISO 10012 or ANSI Z540. Do not force the gage into a bore; excessive insertion force may damage the gage or the workpiece surface.