TSUBOSAN Japan-Hardness Tester Checker File HRC40-HRC65 Set of 6

Excellent quality and super handy for the knife and tool maker to check your hardness after heat treatment. This is a very affordable alternative to expensive HRC machines and worth the money.

I just received these, so haven't used them yet. I noticed the instructions are in Japanese, and other reviewers have commented on it. So, I translated the instructions using the Google translate app on my Android phone. Here it is, without editing: About “hardness check” ■This product comes in a set of 6 and is a measuring tool that can easily test hardness ranging from HRC40 to 65. ■It is easy to carry and is useful when large workpieces cannot be put on a testing machine, or for finding the hardness of steel materials outdoors. ■It is useful for checking the hardness of materials before cutting. ■It is useful for checking whether the hardness achieved after heat treatment is reached or not. ■The grips are available in six different colors and have anti-slip properties. (How to use) ■ Remove any rust from the test material beforehand. If the tester scratches the object when you press and rub it, the hardness is below the hardness indicated on the tester. If the object is not scratched, check it with a tester of the next rank. ■The tip of the tester is bent, so it may be damaged on flat, curved or internal surfaces. The hardness of the radial surface can be checked. (Specification) $4.3×175m (blade length 65㎡) color express red Tester's actual hard surface HRC 40 HRC40~42 HV392~412 HRC 45 HRC45~47 HV446~471 Yellow green HRC 50 HRC50~52 HV513~544 HRC 55 HRC55~57 HV595-633 HRC 60 HRC60~62 HV697~746 black HRC 65 HRC64~66 HV800~865 *The displayed hardness includes an upward error of 2 degrees in HRC. TSUBOSAN FILE CO., LTD.

By golly, the dang things work. I trust them. I used them on mild carbon steel axes I knew from manufacturer specs to be between 50 and 55 rockwell, and that's what these indicated as well. I used them on steel I expected to be at or just under 60, bang on. And then I used them on metal I had suspected was not tempered corrected, sub 50. Well below 50. And guess what? These files told me it was below 45. They worked! (How many times will they work? Well... I figure I'll get my money's worth out of them for my purposes, as I don't need to test EVERYTHING. Just double check when I suspect something is off.

I use these for checking the hardness of axe bits. Resolution is only 5 HRC but that is good enough to seperate the decent quality steel from the cheap junk axes.

Work great and easy to use.

works ok

What a great idea. Make sure you’re testing areas that are going to be covered up with scales. Great quality, great value.

They do exactly what they were intended to do, which is to give you a basic idea of the Rockwell Hardness. Obviously, they are only accurate to +/- 5.0, but that’s the tolerance that’s written on them. I tested them on some know pieces of steel and they performed as expected. As others have said, start with the hardest one and work your way down to the one that slips. You’ll wear them out the other way. Also, the instructions are in Japanese, so if they’re important to you, you either have to spend more for the English version or print them out online and keep that paper with the set.