Absolutely, I had a similar situation when inspecting some thin-walled shafts at my shop. The best solution I found was using a uci portable hardness tester It works with the Ultrasonic Contact Impedance method, so you get accurate readings without significant marks. The probe is tiny and hand-held, so you can measure in tight spaces, curved surfaces, or even gear teeth. It also converts instantly between HRC, HB, and HV, which makes life much easier. I was amazed at how fast and precise it was – literally 1–2 seconds per measurement, and it didn’t damage any delicate components.