Spi 34-212-1 Plug Thread Gage No Go 3-56 2B Single End

Product Description

The SPI 34-212-1 is a single-end No Go plug thread gage designed to inspect and reject internal threads that fall outside the acceptable tolerance range for the 3-56 thread form. Built to 2B classification standards, this gage is used to verify that a threaded hole is not too loose or oversized after tapping. The gage body is machined from steel for durability and dimensional stability. NIST traceability is included, supporting quality-control documentation requirements in precision manufacturing and inspection environments. A size 000 handle is required for use but is not included with this gage.

This gage is suited for quality inspection applications involving miniature 3-56 unified national coarse threads commonly found in small fastener assemblies, instrumentation, and precision mechanical components. It is used by machinists, quality technicians, and inspection personnel working in production or job-shop environments where thread conformance to tolerance class 2B must be verified before parts advance to assembly. The single-end No Go design allows for fast pass-fail inspection without requiring a double-end gage setup.

Key Features

• No Go single-end design for rapid rejection of out-of-tolerance internal threads
• Thread size 3-56 with 2B classification for standard unified thread inspection
• Steel construction for wear resistance and long service life
• NIST-traceable calibration certification included for quality documentation
• Requires size 000 handle, sold separately

Compatibility

Designed for inspection of internal 3-56 unified thread form, 2B tolerance class. Compatible with standard plug gage handles sized for 000 series gages.

Installation Notes

Plug thread gages are handled and used by quality control technicians and machinists — no power tools or utilities need to be shut down for gage use. Always store gages in a protective case away from chips, coolant, and other abrasives to preserve gage accuracy. Do not force the gage into a threaded hole; a No Go gage should not enter a conforming thread. Follow your facility calibration schedule and handle the gage only with clean, dry hands or lint-free gloves to prevent corrosion.