LTDRound file for hardness test
Description
- Very simple to check the hardness of a material. No need to move the material or use a machine. Instructions for use: start with the hardest file and run the file over the material. If there are no marks, the material is harder than the file. Continue by using the other files in descending order of hardness. The approximate hardness of the material is between the hardness of the file that marks and the file that does not mark.
