Ball nose solid carbide: Machine / Spindle size: ISO 40, 50: ISO 40, 50: ISO 30, 40: ISO 30, 40: Stability requirement: High: Medium: Medium: Low: Roughing: Very good: Good: Acceptable: Acceptable: ... When using a ball nose end mill, the most critical area of the cutting edge is the tool center, where the cutting speed is close to zero, which ...