Spi 29-458-7 Class Zz Plus Plug Gage 0.458 in Steel

Product Description

The SPI 29-458-7 is a Class ZZ Plus plug gage designed for go/no-go inspection of bored holes, drilled passages, and machined features at a nominal diameter of 0.458 inches. Built from steel, it delivers a tolerance of 0.0002 inches, meeting Class ZZ Plus dimensional standards for general-purpose inspection work. At 0.2 pounds, the gage is lightweight and easy to handle during repeated measurement cycles. Machinists, quality control technicians, and toolroom professionals use plug gages like this one to verify that hole diameters fall within specified limits without relying on electronic measurement equipment.

This gage is suited for use in production inspection, incoming material verification, and toolroom quality checks across metalworking, machining, and fabrication environments. It is appropriate for both job-shop and higher-volume manufacturing settings where consistent hole-diameter verification is required. The 0.458-inch nominal diameter makes it a fit for applications where close-tolerance hole checking is specified on engineering drawings or inspection plans.

Key Features

• Nominal measurement diameter of 0.458 inches for precise hole inspection
• Class ZZ Plus tolerance of 0.0002 inches (0.0051 mm) for general-purpose accuracy
• Steel construction for durability and dimensional stability under repeated use
• Lightweight at 0.2 pounds for comfortable single-hand operation
• Single-piece package quantity suits individual bench or field inspection setups

Compatibility

Designed as a standard Class ZZ Plus plug gage for general-purpose hole inspection in machined components where a 0.458-inch nominal diameter is specified.

Installation Notes

Plug gages are handled and used by quality control technicians and machinists. Before use, ensure the gage and workpiece are at the same ambient temperature to prevent thermal expansion errors. Clean the gage and the hole being inspected to remove chips, oil, and debris before insertion. Never force a plug gage into a hole; if resistance is felt, remove the gage and investigate the condition of the bore.