Sharp SH-920 Instruction Manual page 39

2.1 Kinds of abrasive
A: For grinding common annealed steels
WA: For grinding steels with higher hardness, such as heat-treated
carbon steel, alloy steel, etc.
H: Suitable for higher hardness steel, particularly high-speed steel
C: For grinding with cast iron and non-ferrous materials.
GC: For super-hard metal grinding such as tungsten carbide
2.2 Grain size:
Coarse: 10, 12, 14, 16, 20, 24
Medium: 30, 36, 46, 54, 60
Fine: 70, 80, 90, 100, 120, 150, 180.
Grain
Size
Grinding
Condition
Stock removal
Surface roughness
Workpiece hardness
Surface contacted
Dia. of the wheel
Coarse
much
rough
soft
wide
big
P.39 OF 70
Fine
little
fine
hard
narrow
small