Osg 1500100500LF Plug Thread Gage 4-40 2B Double End

Product Description

The OSG 1500100500LF is a double-end plug thread gage used to inspect internal 4-40 UNC threads to a 2B tolerance class. The Go end accepts a correctly cut thread while the No Go end rejects any thread that is oversized or out of tolerance. Manufactured from high speed steel for wear resistance and dimensional stability, this gage is a standard inspection tool used by machinists, quality technicians, and production floor personnel verifying threaded holes in precision assemblies. A handle is included. NIST traceability certification is included, supporting documented quality control programs and calibration records.

This gage is suited for inspection of 4-40 threaded holes in light mechanical assemblies, electronic hardware, instrument enclosures, and precision machined components where 2B class fit is specified. The double-end configuration places the Go member on one end and the No Go member on the opposite end of a single handle, reducing changeover time during inspection runs. It is appropriate for both production-floor sampling and incoming inspection applications.

Key Features

• Double-end design with Go and No Go members on a single handle
• Inspects 4-40 UNC internal threads to 2B tolerance class
• Go pitch diameter: 0.0958 inches
• No Go pitch diameter: 0.0991 inches
• High speed steel construction for wear resistance and long service life
• NIST traceability certification included for calibration and quality documentation
• Handle included - no separate purchase required

Compatibility

Designed for inspection of 4-40 UNC internal threaded features held to a 2B tolerance class, as defined by ANSI and ASME thread standards for unified inch screw threads.

Installation Notes

Thread plug gages are inspection instruments and should be handled and stored to avoid damage to the precision-ground surfaces. Apply light gage oil before use to reduce wear and prevent corrosion. Do not force the No Go member into a thread; entry beyond two turns indicates the thread is out of tolerance and the gage should not be forced further. Periodic recalibration against NIST-traceable masters is recommended to maintain measurement integrity.