High quality Japanese made Hardness Test Files are an easy to use, quick and inexpensive tool used to approximate material hardness in Rockwell scale.
Usage is simple. Just slide the test files across the surface, one by one, starting from the hardest until reaching a file soft enough to not record a result. Based on reaching a non-result, the material must be harder than the file with no result and softer than the lowest file that gave a result.
Start with the black file. If it marks the material the hardness of the material is less than 65 HRC. Then proceed to the blue file. If it does not mark the material then the hardness must be between 60 HRC and 65 HRC. If it does mark the material, then proceed to the next file (green.) If it does not mark the material then the result is between 55 HRC and 60 HRC, if it does mark the material then move on accordingly to the next file and so forth.
|COLOUR||INDICATION||FILE HARDNESS||FILE HARDNESS|
|Red||40 HRC||40-42 HRC||392-412 HV|
|Yellow||45 HRC||45-47 HRC||446-471 HV|
|Light Green||50 HRC||50-52 HRC||513-544 HV|
|Green||55 HRC||55-57 HRC||595-633 HV|
|Blue||60 HRC||60-62 HRC||697-746 HV|
|Black||65 HRC||64-66 HRC||800-865 HV|