Balax 90490-000 Plug Thread Insert Go No Go Gage 4-40

Product Description

The BALAX 90490-000 is a double-ended plug thread insert Go/No Go gage designed for inspecting 4-40 STI (Screw Thread Insert) tapped holes to Class 2B tolerance. Manufactured from high speed tool steel, this gage delivers the hardness and wear resistance required for repetitive inspection work in production and maintenance environments. The double-ended configuration places the Go member on one end and the No Go member on the other, both housed in a single included handle, reducing tool changes and speeding up inspection cycles. It conforms to ANSI standards for thread gaging and is used to verify that an STI thread insert installation meets Class 2B fit requirements before assembly proceeds.

This gage is used wherever 4-40 STI threaded inserts are installed and must be verified before mating fasteners are introduced. Typical applications include aerospace, electronics, and precision machined component assembly where thread repair inserts such as helical coil types are used in aluminum, magnesium, or other soft-metal housings. Inspection technicians, machinists, and quality control personnel use this gage as a pass/fail check at the point of assembly or at a dedicated inspection station.

Key Features

• Double-ended design with Go and No Go members on a single handle for efficient inspection
• High speed tool steel construction provides hardness and wear resistance for extended service life
• Inspects 4-40 STI tapped holes to Class 2B tolerance per ANSI standards
• Handle included - no separate handle purchase required
• Conforms to ANSI thread gaging standards for consistent, traceable inspection

Compatibility

Designed for inspection of 4-40 STI (Screw Thread Insert) tapped holes classified to Class 2B tolerance. Suitable for use wherever 4-40 STI inserts are installed and require Go/No Go verification.

Installation Notes

Thread gaging is performed by inspection technicians or machinists and does not require disassembly of live systems, but the workpiece should be secured and free of chips or coolant before gaging. Apply only hand pressure when inserting the Go member - forcing the gage can damage the gage or the thread. The Go member must pass freely through the full thread length, and the No Go member must not enter more than two turns to constitute a passing inspection result. Follow your facility's calibration and gage control procedures to maintain traceability.