Spi 23-171-2 Threaded Ring Gage 7/16-20 Class 2A Go No Go

Product Description

The SPI 23-171-2 is a double-ring threaded ring gage designed to verify external thread conformance on 7/16-20 UNF fasteners and threaded components. Manufactured from tool steel, this gage provides both Go and No Go members in a single double-ring configuration, allowing technicians to confirm that a threaded part falls within the accepted tolerance range for Class 2A fit. The Go ring confirms the minimum material condition is met, while the No Go ring rejects threads that exceed the maximum material limit. NIST traceability certification is included, supporting quality documentation and calibration record requirements in production and inspection environments.

This gage is used in manufacturing, machining, and quality control settings where 7/16-20 UNF external threads must be inspected to Class 2A tolerance standards. Typical applications include incoming inspection of threaded fasteners, in-process thread verification on machined parts, and final inspection before assembly. It is suited for use on the shop floor or in a metrology lab by machinists, quality technicians, and inspectors working to ASME B1 thread standards.

Key Features

• Double-ring design provides both Go and No Go gaging in one tool
• Verifies 7/16-20 UNF external threads to Class 2A tolerance
• Tool steel construction for durability and wear resistance
• NIST traceability certification included for calibration compliance
• Compact size suitable for bench or floor inspection use

Compatibility

Designed for inspection of 7/16-20 UNF external threads manufactured to Class 2A fit tolerances per ASME B1.2 threaded ring gage standards.

Installation Notes

Threaded ring gages are used by machinists and quality inspectors and require no installation in the traditional sense. Handle the gage carefully to avoid dropping or impact damage, which can alter calibration. Store in a clean, dry environment and return for recalibration at intervals consistent with your facility quality management plan. Do not force the No Go ring onto a borderline thread, as this can damage the gage.