Spi 34-349-1 Double End Plug Thread Gage 3-56 2B

Product Description

The SPI 34-349-1 is a double-end plug thread gage designed to verify internal threads sized at 3-56 with a 2B classification. One end checks the Go condition to confirm a thread is within minimum material limits, while the No Go end confirms threads are not over-cut beyond maximum tolerance. The gage is constructed from steel for durability and dimensional stability under repeated use. It ships with a handle included and comes with NIST traceability certification, making it suitable for quality-control environments where documented measurement traceability is required. Machinists, quality inspectors, and precision manufacturing shops are the primary users of this tool.

This gage is used wherever small-fastener internal threads must be verified to ANSI or NIST-referenced standards. The 3-56 thread size is common in miniature assemblies, instrument housings, and precision mechanical components. The double-end design keeps both Go and No Go members on a single handle, reducing tool changeover time during inspection. It is well-suited for production-floor inspection, incoming parts verification, or tool room quality checks in light manufacturing and precision machining environments.

Key Features

• Double-end design with Go and No Go members on one handle
• Checks 3-56 internal threads to 2B classification tolerances
• Steel construction for wear resistance and dimensional consistency
• Handle included — ready to use out of the box
• NIST traceability certification included for documented quality compliance

Compatibility

Designed for inspection of 3-56 class 2B internal threads in miniature fastener and precision assembly applications where NIST-referenced thread verification is required.

Installation Notes

Thread gages are inspection tools, not cutting tools — never force a plug gage into a threaded hole. Clean threads thoroughly before gaging to remove chips, oil, or debris that could affect readings. Store the gage in its case when not in use to protect the precision-ground surfaces. Periodic re-certification against NIST standards is recommended to maintain measurement traceability over time.