Precision hardness testing on small gear teeth

[queenteren]

Hey guys, I need some advice on a tricky NDT task. We have some small gears, and we need to verify the hardness specifically on the tooth flanks. The problem is the geometry—there isn't much flat surface area for a standard tester to sit on. Most of the portable units I've seen have impact bodies that are just too large for this. Is there a handheld solution that can handle very small indentation areas without sacrificing precision? We need to keep the gears intact, so a bench-top Rockwell tester isn't an option.

 

[alejaa]

For gear teeth, you absolutely need the UCI (Ultrasonic Contact Impedance) method. Because it uses a Vickers diamond on a small rod, it can fit into narrow spaces where a Leeb impact body simply can’t go. It’s basically a portable Vickers test. I’ve had great results using specialized probes for thin and small components. You should check the product catalog at https://teqto.pro/portable-hardness-testers as they have several UCI models specifically designed for complex geometries. Just make sure you use a stand or a steady hand to get the most accurate results on those curved surfaces.

 

[queenteren]

Thanks for clarifying the physics behind it, a hybrid device sounds like a smart investment.