Spi 34-250-1 Plug Thread Gage 1/4-20 6H Single End Go

Product Description

The SPI 34-250-1 is a single-end Go plug thread gage designed to verify the minimum material condition of internal 1/4-20 threads to 6H tolerance class. Manufactured from steel, this gage confirms that a threaded hole will accept a mating fastener within specified limits. It is used in inspection, quality control, and production environments where thread conformance to ANSI standards is required. The Go member checks that the thread form, pitch, and diameter fall within the acceptable tolerance range. A size 1 handle is required for use but is not included with this gage.

This gage is suited for dimensional inspection of 1/4-20 internally threaded components in manufacturing, maintenance, and assembly settings. Typical applications include verifying tapped holes in metal parts across general industrial, mechanical, and trade environments. The 6H classification makes it appropriate for standard-fit metric-equivalent unified thread inspection. Machinists, quality technicians, and tool and die professionals commonly use this type of gage on the shop floor or in a gage room setting.

Key Features

• Go-member single-end design checks minimum material condition of 1/4-20 internal threads
• 6H tolerance class conforms to ANSI thread gage standards
• Steel construction for durability in production inspection use
• NIST traceability certification included for calibration documentation
• Meets ANSI and NIST standards for thread gage conformance
• Accepts a size 1 handle (sold separately)

Compatibility

Designed for use with 1/4-20 internally threaded components requiring 6H class Go inspection. Requires a size 1 thread gage handle, which is not included.

Installation Notes

Thread plug gages are installed and operated by hand — no power source or lockout procedure is required. Ensure the threaded bore is clean and free of chips or coolant before gauging to avoid false readings or gage damage. Handle should be securely attached before use per the handle manufacturer's instructions. Gage should be stored and handled per ANSI gage care guidelines to maintain calibration integrity.