... _^*) center drill spot drilling center drill set Row socket drillSuper-hard processing of professional, special, non-standard, ... ≤199mm/min, depth of drilled hole≤2.5*φD(mill Dia.), Precision of processed work piece ≥h9 ... than Ra1.6Extra hard small diameter: mill Dia. φD (φ0.10-φ2.00mm), applicable for machining of ... compound materials, the depth of drilled hole ≤6*φD(mill Dia.)HRF 10 (For super high wear- ...