| ISO | Material | Material Designation | Material Condition | Hardness | Cutting Speed Recommendations (Vc) |
| N | 21 | Aluminum-wrought alloys | Not hardenable | 60 HB | 480-640 m/min |
| N | 22 | Aluminum-wrought alloys | Hardenable | 100 HB | 400-560 m/min |
| N | 23 | Aluminum-cast alloys <=12% Si | Not hardenable | 75 HB | 480-640 m/min |
| N | 24 | Aluminum-cast alloys <=12% Si | Hardenable | 90 HB | 400-560 m/min |
| N | 25 | Aluminum-cast alloys >12% Si | High temperature | 130 HB | 240-320 m/min |
| N | 26 | Copper alloys >1% Pb | Free cutting | 110 HB | 240-320 m/min |
| N | 27 | Copper alloys | Brass | 90 HB | 240-320 m/min |
| N | 28 | Copper alloys | Electrolytic copper | 100 HB | 160-240 m/min |