Spi 34-389-7 Plug Thread Gage 3/8-24 2B Double End Go No Go

Product Description

The SPI 34-389-7 is a double-end plug thread gage used to verify internal threads to the 3/8-24 UNF thread standard at 2B class tolerance. One end carries the Go member and the opposite end carries the No Go member, allowing a technician to confirm both the minimum and maximum thread tolerance limits in a single tool. The gage is machined from steel for dimensional stability and long service life. A handle is included, sized at Handle Size 2, so the gage is ready to use out of the box. NIST traceability certification is included, supporting quality and calibration documentation requirements in shop and field inspection programs.

This plug thread gage is suited for use in precision machining, fabrication, and maintenance environments where 3/8-24 UNF internally threaded fastener holes, fittings, or components must be verified to 2B class tolerances. It is appropriate for incoming inspection, in-process quality checks, and toolroom verification tasks. Machinists, quality control inspectors, and maintenance technicians are the primary users. The included NIST traceability certificate makes this gage compatible with ISO and AS9100 quality management system documentation requirements.

Key Features

• Double-end design: Go and No Go members on a single gage for efficient tolerance verification
• Thread specification: 3/8-24 UNF at 2B class tolerance
• Steel construction for dimensional stability and durability under repeated use
• Handle Size 2 included — no separate handle purchase required
• NIST traceability certification included for quality system and calibration records
• Single-package unit ready for immediate deployment in inspection or shop environments

Compatibility

Designed for inspection of internal 3/8-24 UNF threads at 2B class tolerance. Verify that the thread form, pitch, and class of the workpiece match these specifications before use.

Installation Notes

Thread gages do not require installation but should be handled and stored in accordance with standard metrology practices to preserve accuracy. Always clean threads on the workpiece before gaging to avoid false rejections or gage wear. Do not force the Go member — hand-tight engagement under light pressure is the accepted technique. Calibrate or re-certify the gage at intervals appropriate to your quality management system requirements.