Spi 34-253-5 Plug Thread Gage 1/4-28 6H Single End Go

Product Description

The SPI 34-253-5 is a single-end Go plug thread gage designed to verify internal thread conformance on 1/4-28 UNF threaded holes. Built to a 6H tolerance class, it checks that threads fall within the acceptable minimum material condition, confirming a mating fastener will engage properly. The gage body is machined from steel for durability and dimensional stability under repeated use. A size 1 handle is required for operation but is sold separately. This tool is traceable to NIST standards and conforms to ANSI specifications, making it suitable for quality control applications in precision manufacturing and mechanical assembly environments.

This Go plug gage is used by machinists, quality control technicians, and precision manufacturing professionals to inspect tapped holes in production and repair settings. It is appropriate for incoming inspection, in-process verification, and final QC checks on components requiring 1/4-28 UNF internal threads. The single-end Go configuration is the correct choice when a dedicated Go-only check is needed, separate from a No-Go gage used in the same inspection process.

Key Features

• Go-type single-end plug gage for 1/4-28 UNF internal threads
• 6H tolerance class for standard-fit thread verification
• Steel construction for wear resistance and dimensional stability
• NIST-traceable calibration included for documentation and compliance
• Conforms to ANSI and NIST standards
• Accepts a size 1 handle (handle sold separately)

Compatibility

Designed for use with size 1 plug gage handles to inspect 1/4-28 UNF tapped holes held to a 6H tolerance class. Handle is not included and must be sourced separately.

Installation Notes

This gage is installed by a quality technician or machinist into a compatible size 1 handle before use. Do not force the gage through a tapped hole; the Go member should pass through a conforming thread with hand pressure only. Store the gage in a protective case away from other metal tools to prevent nicking the thread form. Verify calibration status and NIST traceability documentation before use in a formal inspection process.