Osg 1500101800 Plug Thread Gage 1/4-28 2B Double End

Product Description

The OSG 1500101800 is a double-end plug thread gage used to verify internal thread conformance to 1/4-28 UNF specifications at a 2B tolerance class. The Go end checks that the threaded hole accepts a mating fastener without interference, while the No Go end confirms the thread has not been cut oversized. Made from high speed steel, this gage delivers the hardness and dimensional stability required for consistent inspection results in production or field quality-control environments. A handle is included. Machinists, quality technicians, and precision tool trades use this type of gage as part of standard thread inspection workflows.

This gage is suited for inspecting 1/4-28 UNF tapped holes in metal components across manufacturing, aerospace, automotive, and general mechanical assembly applications. The 2B classification covers the standard tolerance range for most commercial threaded fastener applications. The double-end design consolidates Go and No Go functions into a single tool, reducing the number of gages required at an inspection station. It is appropriate for both shop-floor use and incoming or outgoing quality inspection.

Key Features

• Double-end design with Go and No Go members in a single gage
• Inspects 1/4-28 UNF internal threads to 2B tolerance class
• High speed steel construction for wear resistance and dimensional stability
• Handle included — ready to use out of the box
• Compact overall length of 3 inches for easy handling at the inspection station

Compatibility

Designed for inspection of 1/4-28 UNF internally threaded features held to a 2B tolerance class. Suitable for use anywhere that standard UNF thread verification is required per applicable thread standards.

Installation Notes

Thread gages are inspection tools, not cutting tools — they should never be forced into a tapped hole. Apply the Go member by hand with light rotational pressure; it should pass through the full thread length without binding. The No Go member should not enter more than two turns. Clean the gage and the part before each check to prevent debris from causing false readings, and store the gage in its protective case when not in use to maintain calibration integrity.