Spi 34-379-8 Double End Plug Thread Gage 1/4-32 2B

Product Description

The SPI 34-379-8 is a double-end plug thread gage designed to inspect 1/4-32 threads to the 2B tolerance class. One end carries the Go member and the opposite end carries the No Go member, allowing a technician to confirm both minimum and maximum thread acceptance in a single tool. The gage is machined from steel for dimensional stability and comes with a Size 1 handle included. A NIST-traceable traceability certification ships with the unit, satisfying quality-system documentation requirements without additional calibration steps at incoming inspection.

This gage is used in precision machining, metrology labs, and quality-control environments where 1/4-32 threaded components must be verified before assembly or shipment. The 2B classification covers the standard commercial tolerance for inch-series internal threads, making this tool appropriate for production inspection of fittings, fasteners, and instrument ports machined to that specification. Inspection technicians and quality engineers are the primary users.

Key Features

• Double-end design: Go member on one end, No Go member on the other for complete thread acceptance testing in one tool
• Thread specification: 1/4-32 inch-series internal thread
• Tolerance class: 2B, standard commercial fit for internal threads
• Steel construction for dimensional stability under repeated use
• Size 1 handle included — no separate handle purchase required
• NIST-traceable certification included, supporting ISO and quality-system audit requirements

Compatibility

Designed for inspection of 1/4-32 Class 2B internal threads in machined components, fittings, and fastener applications where inch-series thread gaging is required.

Installation Notes

Plug thread gages are inspection tools and do not require installation in a mechanical system. Handle the gage with clean, dry hands or lint-free gloves to prevent corrosion on the precision-ground surfaces. Store in the provided case or a protected location when not in use to maintain calibration integrity. Periodic re-calibration against NIST standards should follow your facility's gage control plan.