Dưỡng kiểm ren ngoài GO chính xác (Tol. 2A) - UNC 3/8 x 16

• Quick verification of ren ngoài dimensions per UNC 3/8-16
• Easy to use – no special metrology skills required
• High precision and repeatable results
• Suitable for any production method (turning, rolling, milling, etc.)
• Optional factory calibration certificate; calibrated in an independent laboratory

Testing note: The gauge must fully screw onto the thread by hand at 20 °C without force. Otherwise, the part is out of tolerance.

• UNC (Unified National Coarse): Inch-based coarse thread form within the Unified Thread Standard, e.g. 3/8-16 (diameter / threads per inch).
• ANSI B1.1: Defines geometry, tolerances, and classes (1A/2A/3A for external, 1B/2B/3B for ren trong).
• ANSI B1.2: Defines gauge dimensions and inspection principles for Unified threads (GO/NO-GO gauges).
• Tolerance Class 2A: Standard production quality with controlled clearance; pairs with 2B ren trong.

1. 1. Preparation: Clean and deburr the ren ngoài; stabilize the environment to 20 °C.
2. 2. Engagement: Align the gauge squarely with the thread start.
3. 3. Testing: Screw the gauge manually over the entire thread without force.
4. 4. Evaluation: Full manual engagement = OK. Resistance or incomplete travel = Reject.
5. 5. Documentation: Record inspection results and gauge identification if required.

Why is the reference temperature 20 °C?
Thermal expansion affects dimensions. 20 °C ensures consistent and comparable measurements.

What is the difference between 2A and 3A?
3A provides a tighter fit with less clearance, used for precision assemblies. 2A is standard for general production.

Can I order it calibrated?
Yes, a factory calibration certificate can be issued upon request.

When is a part considered scrap?
If the GO gauge cannot be fully screwed by hand without force, the thread is out of tolerance.

Do I need extra measuring tools?
No, for GO testing the ring gauge is sufficient. For full dimensional analysis, dedicated measuring equipment is required.