Spi 34-261-8 Plug Thread Gage 5/16-18 No Go 6H

Product Description

The SPI 34-261-8 is a single-end No Go plug thread gage designed to verify that an internal thread does not exceed its maximum material condition. Built to a 6H classification, this steel gage checks 5/16-18 UNC threads and confirms the thread profile falls within tolerance. It is used in precision inspection, quality control, and production-floor verification tasks where thread acceptance standards must be documented. The gage ships without a handle — a Size 1 handle is required separately for proper use. NIST traceability certification is included, supporting compliance with ANSI inspection standards.

This gage is suited for machine shops, manufacturing facilities, and industrial maintenance environments where threaded fastener holes must be inspected before assembly. The No Go member rejects threads that are oversize or improperly formed, catching machining errors before components reach the line. It is appropriate for any application requiring documented thread inspection to ANSI and NIST standards on 5/16-18 internal threads.

Key Features

• No Go plug gage verifies that internal threads do not exceed maximum material condition
• 6H classification for standard-tolerance metric-style fit on 5/16-18 UNC threads
• Steel construction for durability in repeated inspection use
• NIST traceability certification included for documented quality compliance
• Single-end design for dedicated No Go inspection workflow
• Requires a Size 1 handle, sold separately

Compatibility

Designed for use with 5/16-18 UNC internal threads inspected to 6H classification under ANSI standards. Accepts a standard Size 1 thread gage handle, not included.

Installation Notes

Thread plug gages are installed and used by machinists, quality inspectors, and tool-room technicians. Before use, verify the gage handle is properly seated and secure. The No Go member should not enter a conforming thread — if it does, the thread is out of tolerance and the part should be rejected. Handle gages with care to avoid dropping or contact with abrasive surfaces, which can affect calibration.