TSUBOSAN 金屬硬度銼 HRC40~HRC65

Tsubosan Hardness Tester Files: a simple experimental tools for hardness between HRC40 ～ 65. Very convenient pocket size hardness tester.
Each file is color coded, and hardness is printed onto handle.

Using direction : pick the hardest file and scratch onto testing surface, if scratch line appear then use softer file until no scratch line appear. The hardness of the testing object then should be between the non-scratching file and the scratching file.