Spi 34-436-6 Pipe Thread Plug Gage 3/8-18 Npt Class L-1

Product Description

The SPI 34-436-6 is a tapered pipe thread plug gage used to verify the accuracy of internal NPT pipe threads to Class L-1 tolerance. Designed for single-end use with a size 3 handle, this gage checks that threaded pipe connections meet the dimensional requirements of ANSI B1.20.1. Each unit ships with a NIST Traceability Certificate, making it suitable for use in quality-controlled environments where documentation is required. Plumbers, pipefitters, and inspection technicians rely on plug gages like this to confirm thread form and engagement length before assembly, reducing the risk of leaking joints in pressurized piping systems.

This gage is used in pipe fabrication shops, mechanical contractor workflows, and quality assurance inspection stations. The 3/8-18 designation indicates a 3/8-inch nominal pipe size with 18 threads per inch, a common size found in residential and light commercial plumbing, gas distribution, and hydraulic piping. It is appropriate for any application where NPT-threaded fittings or couplings must meet L-1 class go-gage acceptance criteria before installation.

Key Features

• Tapered NPT-L1 thread form per ANSI B1.20.1 standard
• Class L-1 tolerance for go-gage verification of internal pipe threads
• 3/8-18 thread size covers a widely used nominal pipe size
• Single-end design with size 3 handle for secure grip during inspection
• Includes NIST Traceability Certificate for quality and calibration documentation

Compatibility

Designed for inspecting internal tapered NPT pipe threads at 3/8-18 thread size to Class L-1 acceptance standards per ANSI B1.20.1.

Installation Notes

Thread plug gages are inspection instruments and should be handled by qualified inspection or trades personnel familiar with go/no-go gaging procedures. Keep the gage clean and lightly oiled when not in use to prevent corrosion and wear. Do not force the gage into a threaded workpiece; excessive torque can damage both the gage and the part being inspected. Store in a protective case away from impact and temperature extremes to maintain calibration integrity.