Spi 34-252-7 No Go Plug Thread Gage 1/4-20 6H

Product Description

The SPI 34-252-7 is a single-end No Go plug thread gage used to verify internal thread quality on 1/4-20 threaded features. It checks that a tapped hole has not been cut oversize, ensuring threads fall within the tolerance boundaries defined by the 6H classification. Manufactured from steel, this gage is NIST traceable and conforms to ANSI standards, making it suitable for use in quality control, incoming inspection, and production-floor verification. A size 1 handle is required for use but is not included with this gage. Installation of the handle is the responsibility of the end user.

This gage is used wherever 1/4-20 internal threads must be confirmed to specification before assembly. Common applications include machining shops, fabrication facilities, and manufacturing environments where threaded fastener joints are subject to engineering tolerances. The No Go member is used in conjunction with a separate Go gage to confirm both minimum and maximum thread acceptance criteria. It is appropriate for use on ferrous and non-ferrous workpieces in both job-shop and production-line settings.

Key Features

• No Go member verifies internal 1/4-20 threads are not oversize per 6H tolerance class
• Steel construction for wear resistance and dimensional stability
• NIST traceable certification included for documented quality system compliance
• Conforms to ANSI standards for thread gage requirements
• Single-end design for straightforward No Go inspection use
• Requires a size 1 handle, sold separately

Compatibility

Designed for inspection of 1/4-20 internal threads manufactured to 6H tolerance class per ANSI and NIST standards. No Go function is intended to be used alongside a corresponding Go plug gage for complete thread acceptance verification.

Installation Notes

Thread plug gages are precision metrology instruments handled by quality technicians or machinists. Mount the gage into a compatible size 1 handle before use. Do not force the No Go member into a conforming thread; if it enters the threaded hole, the part is out of tolerance. Store gages in a protective case away from chips, coolant, and abrasive contaminants to preserve calibration integrity.