Spi 34-391-3 Plug Thread Gage 3/8-32 2B Go No Go

Product Description

The SPI 34-391-3 is a double-end plug thread gage used to inspect 3/8-32 unified internal threads to 2B tolerance class. One end carries the Go member; the opposite end carries the No Go member. A handle is included. The Go end confirms that the thread falls within minimum material limits, while the No Go end confirms that the thread does not exceed maximum material limits. This gage is manufactured from steel and ships with a traceability certification traceable to NIST standards. It is used by machinists, quality technicians, and inspection personnel to verify threaded holes during production and incoming inspection.

The 34-391-3 is suited for inspecting 3/8-32 threaded bores in a machine shop, manufacturing floor, or inspection room setting. The double-end configuration reduces tool changeover time during go/no-go thread inspection routines. The included handle is size 2, compatible with the gage members supplied. This gage is appropriate for both production floor use and receiving inspection of threaded components requiring 2B class thread verification.

Key Features

• Double-end design with Go and No Go members on a single handle for efficient inspection
• Inspects 3/8-32 unified internal threads to 2B tolerance class
• Steel construction for durability and dimensional stability
• NIST-traceable traceability certification included
• Handle size 2 included — no separate purchase required

Compatibility

Designed for inspection of 3/8-32 internal threads classified to 2B tolerance per unified thread standards. Compatible with size 2 plug gage handles.

Installation Notes

Plug thread gages are handled by quality control technicians or machinists. Before use, clean the threaded bore and gage members to remove chips, oil, or debris that could affect readings. Apply light gage oil if required to reduce wear on the gage members. Store the gage in its case when not in use to protect the thread members from damage that would affect calibration integrity.