Spi 34-442-4 Pipe Thread Plug Gage 2-11-1/2 Npt L-1

Product Description

The SPI 34-442-4 is a tapered pipe thread plug gage used to verify the dimensional conformance of internal NPT threads to Class L-1 tolerances. Engineered to ANSI B1.20.1 standards, this single-end gage gives pipe fitters, quality inspectors, and machinists a reliable go/no-go reference for 2-11-1/2 NPT threaded bores. The gage ships with a Handle Size 5 and includes a NIST Traceability Certificate, confirming calibration lineage to national measurement standards. At 1 pound, it is a manageable bench or field tool built for production inspection and quality-assurance workflows.

This gage is applied wherever precision internal NPT thread verification is required, including pressure fittings, pipe couplings, valves, and manifolds found in plumbing, HVAC, and industrial piping systems. The Class L-1 designation makes it appropriate for standard-engagement thread checks on 2-11-1/2 NPT bores, covering both commercial and light industrial inspection scenarios. It is commonly used by QC departments, calibration labs, and journeyman trades requiring documented thread conformance on critical pipe connections.

Key Features

• Tapered NPT-L1 thread form conforming to ANSI B1.20.1 for standardized inspection
• Class L-1 tolerance for standard engagement thread verification on 2-11-1/2 NPT internal threads
• Single-end design with Handle Size 5 for controlled, repeatable gage engagement
• Includes NIST Traceability Certificate to support documented quality and calibration requirements
• Lightweight at 1 pound for easy bench or field handling

Compatibility

Designed for inspection of 2-11-1/2 NPT Class L-1 internal tapered pipe threads per ANSI B1.20.1.

Installation Notes

Thread plug gages are inspection tools and should be handled by qualified QC technicians or calibrated trade professionals. Apply thread gage lubricant sparingly before use to protect the gage threads and ensure accurate engagement. Do not force the gage into the bore; excessive torque can damage both the gage and the workpiece thread. Store in a protective case away from contaminants to preserve calibration integrity.