| ISO | Workpiece Material Group | Material Designation | Material Condition | Hardness | Cutting Speed Recommendations (Vc) |
| N | 21 | Aluminum-wrought alloy. | Not cureable | 60 HB | 300-2000 m/min |
| N | 22 | Aluminum-wrought alloy. | Cured | 100 HB | 300-2000 m/min |
| N | 23 | Aluminum-cast, alloyed <12% Si. | Not cureable | 75 HB | 200-1300 m/min |
| N | 24 | Aluminum-cast, alloyed. | Cured | 90 HB | 200-1300 m/min |
| N | 25 | Aluminum-cast, alloyed >12% Si. | High temperature | 130 HB | 80-800 m/min |
| N | 26 | Copper alloys >1% pb. | Free cutting | 110 HB | 60-500 m/min |
| N | 27 | Copper alloys. | Brass | 90 HB | 60-500 m/min |
| N | 28 | Copper alloys. | Electrolitic copper | 100 HB | 30-360 m/min |
| N | 29 | Non metallic. | Duro& fiber plastics | 60 HB | 100-800 m/min |
| N | 30 | Non metallic | Hard rubber | 55 HB | 100-500 m/min |