Table 1 Specification of hollow drill tool and twist drill bit
Diamond coated hollow drill tool | Twist drill bit | ||
|---|---|---|---|
Outer diameter | 4.5 | Number of cutting lips | 2 |
Inner diameter | 2.9 | Helix angle: | 8.4° |
Mesh size | 80–100 | Point angle | 120° |
Areal average abrasive/grain density | 15 abrasive/mm2 | Tool base material: | Stainless steel |
Abrasive/grain type | Diamond | Â | Â |
Tool shank material | EN-31 | Â | Â |
Abrasive/grain coated method | Electroplating | Â | Â |