There are 4 general representations of gear hardness.

1. Rockwell Hardness (HRC)

2. Shore Hardness (HS)

3. Vickers Hardness (HV)

4. Brinell Hardness (HBS)

The following table shows the correspondence between 4 different representations of gear hardness. Save it for a rainy day.

gear hardness table
Gear Hardness Table