Rockwell Hardness Testing Procedures

10 kg minor load
100 kg major load
1/16" diameter, hardened steel indenter

Procedures

1. Pull back handle to set the major load.
2. Position the specimen and tighten it up until the small needle is on the dot. This applies the minor load.
3. Align the "set" mark with the large indicator needle.
4. Push the button or lever.
5. After motion of indicator needle has stopped for 3 to 5 seconds, pull back handle carefully to release the major load.
6. Read the Rockwell B hardness number using the red scale, or read the Rockwell C hardness number using the black scale.
7. Repeat until three Rockwell measurements have been made and then average the results. (Additional tests may be performed if values are not in reasonably close agreement.)
8. Estimate the tensile strength from the average Rockwell hardness number using the conversion chart on the wall.