Fowler's Hardness Tester File Set is an inexpensive, easy-to-use method for determining material hardness by sliding the file across the object's surface. Six color coded files indicate hardness from 40 to 65 HRC. Conveniently packaged in a leather-like case with a velcro lined flap, the files are approximately .157" in diameter and 7" in length (4.3Ø x 175mm). Testing Procedure: Run the Black file (65 HRC) over test material. If it marks the material, the material is less than 65 HRC. Try the Blue file (60 HRC). If it does not mark the material, it indicates that the file is softer than the material and is between 60 and 65 HRC. If the Blue file (60 HRC) marked the material, continue testing with the Green (55 HRC), Light-Green (50 HRC), etc. until the material is not marked. The approximate hardness of the material is between the file that marks the material and the file that slides over the material. Included chart also shows the appropriate Vickers Hardness (HV).
