Spi 29-399-3 Class Zz Plus Plug Gage 0.399 in

Product Description

The SPI 29-399-3 is a Class ZZ Plus plug gage machined for dimensional inspection of holes and bores at 0.399 inches in diameter. Built from steel, it delivers a tolerance of 0.0002 inches, making it suitable for go/no-go verification tasks in quality control and in-process inspection environments. This type of gage is a standard precision tool found in machine shops, manufacturing cells, and anywhere close-tolerance bore verification is required. Machinists, quality technicians, and tool-and-die professionals rely on Class ZZ plug gages for repeatable, accurate measurement without complex setup.

This plug gage is appropriate for use in production inspection of drilled, reamed, or bored holes where the nominal diameter is 0.399 inches. It fits standard inspection workflows for light manufacturing and general industrial applications. The Class ZZ Plus designation indicates a tighter tolerance specification than standard Class ZZ gages, supporting more demanding inspection requirements in residential or commercial production environments.

Key Features

• 0.399 inches nominal diameter for direct bore verification
• 0.0002 inches tolerance for close-tolerance inspection work
• Steel construction for durability and dimensional stability
• Class ZZ Plus designation for tighter-than-standard gage accuracy
• Single-piece package quantity for individual tool management

Compatibility

Designed as an OEM-style replacement or direct-use precision gage for any application requiring go/no-go plug gage inspection at a 0.399-inch nominal bore diameter.

Installation Notes

Plug gages are handled and used by quality technicians and machinists and require no permanent installation. Store the gage in its case when not in use to protect the precision ground surfaces from damage. Clean bore and gage surfaces before use to prevent false readings. Do not force the gage into a hole; if resistance is felt, inspect the bore for burrs or contamination before proceeding.