This new innovative file set provides a quick, inexpensive and simple way to check material hardness. No need to bring the material to be tested over to a hardness testing machine, great for those object too large to use bench-top testers on. Just bring this file set (6 files from 40 to 65 HRC) to the piece to be tested. Follow these simple steps to test your material:

  1. Start with the BLACK handle file(65 HRC)and run the file over the test material. If it marks the material, the material is less than 65 HRC.
  2. Try the BLUE handle file(60 HRC):If it does not mark the material, the file is softer than the material. In this case the material is between 60 and 65 HRC.
  3. If the BLUE handle file(60 HRC)did mark the material, simply try the GREEN file(55 HRC), the LIGHT-GREEN handle file(50 HRC), and continue until the material is not marked. The approximate hardness of the material is between the file that marks the material and the file that slips over the material.