Spi 34-289-9 Plug Thread Gage 1/2-20 6H Single End Go

Product Description

The SPI 34-289-9 is a single-end Go plug thread gage machined from steel and designed to verify internal thread dimensions to ANSI standards. It checks whether a 1/2-20 UNF threaded hole meets the minimum acceptable material condition, confirming that a mating fastener will assemble correctly. Classified to 6H tolerance, this gage delivers the precision required for quality control in manufacturing, machining, and maintenance environments. A NIST traceability certification is included, supporting documentation requirements in regulated inspection workflows. Handle is not included; the gage accepts a Size 2 handle sold separately.

This plug thread gage is used wherever internal 1/2-20 UNF threads must be verified before assembly or acceptance. Typical applications include machine shops, production lines, aerospace and automotive component inspection, and maintenance facilities performing critical fastener verification. It is suited for both incoming inspection and in-process quality checks. Machinists, quality control technicians, and tool-and-die professionals are the primary users of this gage.

Key Features

• Go single-end design checks minimum material condition of internal 1/2-20 UNF threads
• 6H classification provides precision tolerance appropriate for general-purpose threaded connections
• Steel construction for durability in production and shop floor inspection environments
• NIST traceability certification included for compliance with documented quality systems
• Accepts Size 2 handle for standard plug gage handle systems (handle not included)
• Conforms to ANSI and NIST standards for thread gage accuracy

Compatibility

Designed for use with standard Size 2 plug gage handles. Verifies internal threads with a 1/2-20 UNF thread form to 6H tolerance class per ANSI standards.

Installation Notes

Thread gages should be handled and stored carefully to prevent damage to the gage member surfaces. Before use, ensure the gage and workpiece threads are clean and free of chips, oil, or debris that could affect the measurement result. Apply light, even hand pressure when inserting the Go member — do not force the gage. Periodic recalibration against NIST-traceable standards is recommended to maintain measurement integrity.