Spi 34-406-9 Plug Thread Gage 9/16-12 3B Go No Go

Product Description

The SPI 34-406-9 is a double-end plug thread gage used to verify internal thread dimensions to 9/16-12 UNC specifications at 3B tolerance class. One end carries the Go member and the opposite end carries the No Go member, allowing a technician to confirm both minimum and maximum thread tolerance in a single tool. The gage is constructed from steel and ships with a size 3 handle included. NIST traceability certification is included, making this gage suitable for quality-control environments where documented calibration standards are required. Machinists, tool-and-die technicians, and quality inspectors use this type of gage on production floors and in inspection labs.

This gage is applied wherever internal 9/16-12 UNC threads must be verified against 3B class tolerance limits. Typical use cases include receiving inspection of threaded components, in-process thread verification during machining, and final inspection before assembly. The double-end design reduces tool changeover time compared to single-end gages, which is an advantage in high-volume inspection workflows. The included handle keeps the gage ready to use out of the box without requiring a separate handle purchase.

Key Features

• Double-end design with Go and No Go members in one tool
• Thread size 9/16-12 UNC at 3B class tolerance
• Steel construction for durability in production environments
• Size 3 handle included — no separate handle required
• NIST traceability certification included for documentation-required inspection processes

Compatibility

Designed for inspection of internal 9/16-12 UNC threads manufactured to 3B class tolerance per applicable NIST and ASME thread gage standards.

Installation Notes

Thread plug gages are handled and stored by quality inspectors and machinists — they are precision measuring instruments, not installation hardware. Keep the gage clean and lightly oiled when not in use to prevent corrosion. Do not force the Go or No Go end into a threaded hole; apply only light hand pressure. Store the gage in its protective case away from other metal tooling to prevent contact damage that could affect gage accuracy.