Spi 34-362-4 Plug Thread Gage 6-40 3B Double End

Product Description

The SPI 34-362-4 is a double-end plug thread gage designed to verify internal thread conformance to a 6-40 thread specification at a 3B class of fit. One end carries the Go member; the opposite end carries the No Go member. The Go end confirms the thread will accept a mating fastener within the tolerance boundary. The No Go end confirms the thread has not been cut oversize. The gage ships with a handle included and comes with an NIST-traceable traceability certification, making it suitable for quality-controlled manufacturing and inspection environments. Steel construction provides the dimensional stability required for repeatable gauging results.

This gage is used wherever internal 6-40 threads must be verified to 3B tolerance class — common in precision machining, aerospace sub-assembly, electronics hardware, and instrument manufacturing. The double-end configuration consolidates Go and No Go verification into a single tool, reducing changeover time during inspection. A handle is included, so the gage is ready to use out of the package. It is appropriate for incoming inspection, in-process quality checks, and final acceptance gauging on tapped holes.

Key Features

• Double-end design with Go and No Go members on a single gage body
• Calibrated to 6-40 thread size at 3B class of fit
• Steel construction for dimensional stability and wear resistance
• NIST-traceable traceability certification included for quality system compliance
• Handle included — no separate purchase required

Compatibility

Designed for inspection and verification of internal 6-40 tapped holes held to a 3B class of fit per applicable thread standards.

Installation Notes

Thread gages are inspection tools, not cutting tools — they should never be forced into a tapped hole. Insert the Go end by hand with light torque; it should pass fully through a conforming thread. The No Go end should not enter beyond two turns on a conforming thread. Store the gage in its protective case when not in use and periodically verify calibration status against your quality system requirements to maintain NIST traceability.