Spi 34-290-7 Plug Thread Gage 1/2-20 6H No Go

Product Description

The SPI 34-290-7 is a single-end plug thread gage designed to inspect 1/2-20 UNF internal threads to a 6H tolerance class. It is configured as a No Go member, meaning it verifies that a threaded hole has not been cut oversized or out of tolerance. The gage body is machined from steel for dimensional stability and wear resistance. A size 2 handle is required for use but is not included with this gage. Traceability documentation conforming to NIST standards is included, supporting quality-control and calibration recordkeeping requirements in production and inspection environments.

This gage is used in machine shops, manufacturing facilities, and field inspection settings where 1/2-20 UNF threaded components must meet ANSI thread tolerance specifications. It is suited for incoming inspection, in-process quality checks, and final verification of tapped holes in metal parts. The single-end No Go design is typically paired with a separate Go gage to complete a full thread acceptance check per standard gaging practice.

Key Features

• No Go plug member for 1/2-20 UNF internal thread inspection
• 6H tolerance class per ANSI thread standards
• Steel construction for durability and dimensional stability
• NIST traceability certification included for calibration recordkeeping
• Conforms to ANSI and NIST standards
• Size 2 handle interface — handle sold separately

Compatibility

Designed for use with a standard size 2 gage handle (not included) and intended to inspect 1/2-20 UNF internal threads to 6H classification per ANSI standards.

Installation Notes

Thread gages are installed and used by quality-control technicians and machinists — no power tools or shutoff procedures are required. Handle should be properly seated before use to ensure accurate and repeatable readings. Do not force the No Go gage into a thread; resistance at entry indicates the thread is within acceptable tolerance. Store the gage in a protective case away from contaminants to maintain calibration integrity.