Spi 34-329-3 Plug Thread Gage 7/8-20 6H Single End No Go

Product Description

The SPI 34-329-3 is a single-end No Go plug thread gage designed to verify internal thread conformance to the 7/8-20 thread form at 6H tolerance class. Manufactured from steel, this gage checks whether a threaded hole falls outside the acceptable tolerance range, rejecting parts that do not meet specification. It is a standard inspection tool used on the shop floor, in quality labs, and at receiving inspection stations. NIST traceability is included, supporting documentation requirements in regulated manufacturing and calibration-controlled environments. A size 4 handle is required for use but is sold separately.

This gage is suited for production inspection of 7/8-20 internally threaded components in machining, assembly, and manufacturing operations. It is appropriate for both high-volume production lines and low-volume precision work where thread quality must be verified against ANSI standards. The single-end No Go configuration is typically paired with a Go gage to complete a full thread inspection routine. Handle not included — order a compatible size 4 plug gage handle separately before use.

Key Features

• No Go member checks that internal threads do not exceed the maximum material condition limit for 7/8-20 at 6H class
• NIST traceability certification included, meeting documentation needs for ISO and AS9100 quality systems
• Conforms to ANSI and NIST standards for thread gage manufacture and calibration
• Steel construction provides durability and dimensional stability under repeated inspection use
• Single-end design for straightforward No Go-only inspection workflows
• Size 4 handle interface — compatible with standard plug gage handles (handle sold separately)

Compatibility

Designed for use with size 4 plug gage handles to inspect internally threaded workpieces with a 7/8-20 thread form at 6H tolerance class per ANSI standards.

Installation Notes

Thread gages should be handled and stored according to standard metrology practices to preserve accuracy. Before use, clean both the gage member and the threaded hole to remove chips, oil, and debris that could produce false readings. Do not force the No Go member into a threaded hole — proper technique relies on hand pressure only, and resistance or free passage determines acceptance or rejection. Gages should be recalibrated at intervals appropriate to usage frequency and the calibration management requirements of the governing quality system.