Spi 34-353-3 Plug Thread Gage 4-48 2B Double End Go No Go

Product Description

The SPI 34-353-3 is a double-end plug thread gage designed to verify internal thread quality on 4-48 UNC threaded holes. One end carries the Go member; the other carries the No Go member, allowing a technician to confirm both minimum material condition and maximum material condition in a single tool. The gage is manufactured from steel and conforms to 2B class thread tolerances. A handle is included. A NIST-traceable traceability certification ships with the gage, supporting documented quality control programs in precision machining, assembly, and inspection environments.

This gage is suited for production floor inspection, incoming inspection, and tool room verification of small-diameter 4-48 threaded features. The 4-48 thread size appears frequently in instrument hardware, miniature fastener assemblies, electronic enclosures, and precision mechanical components. Machinists, quality technicians, and inspection personnel use this tool to accept or reject tapped holes before assembly proceeds, reducing costly rework downstream.

Key Features

• Double-end design combines Go and No Go members in one gage for efficient single-setup inspection
• 4-48 thread size with 2B class tolerance for standard internal thread verification
• Steel construction for durability in production and tool room environments
• Handle included — no separate handle purchase required
• NIST-traceable certification included to support ISO and quality management documentation requirements

Compatibility

Designed for inspection of internal 4-48 class 2B threaded holes in any material or component where that thread form is specified.

Installation Notes

Plug thread gages are hand-applied inspection tools and require no permanent installation. The Go member should pass fully through the threaded hole under finger force only — never force it with a wrench or power tool. The No Go member should not enter the hole more than two turns; if it does, the thread is out of tolerance. Store the gage in its case when not in use to protect the thread members from damage and contamination.