| ISO | Workpiece Material Group | Material Designation | Material Condition | Hardness | Cutting Speed Recommendations (Vc) |
| N | 21 | Aluminum-wrought alloy. | Not cureable | 60 HB | 550-700 m/min |
| N | 22 | Aluminum-wrought alloy. | Cured | 100 HB | 600-750 m/min |
| N | 23 | Aluminum-cast, alloyed <12% Si. | Not cureable | 75 HB | 800-900 m/min |
| N | 24 | Aluminum-cast, alloyed. | Cured | 90 HB | 650-800 m/min |
| N | 25 | Aluminum-cast, alloyed >12% Si. | High temperature | 130 HB | 250-320 m/min |
| N | 26 | Copper alloys >1% pb. | Free cutting | 110 HB | 300-400 m/min |
| N | 27 | Copper alloys. | Brass | 90 HB | 300-400 m/min |
| N | 28 | Copper alloys. | Electrolitic copper | 100 HB | 210-280 m/min |
| N | 29 | Non metallic. | Duro& fiber plastics | 60 HB | 150-250 m/min |
| N | 30 | Non metallic | Hard rubber | 55 HB | 150-250 m/min |