Roll forged from HSS, ensuring uninterrupted grain structure. This provides exceptional strength and durability. Tips are ground for effective cutting. Suitable for drilling wood, plastic, carbon and plain steels where the cutting efficiency of ground flute is not required. Manufactured to BS 328 : Part 1 : 1986 & DIN 338 Type N. 41 Piece Set Contents (mm): 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 9.0, 9.1, 9.2, 9.3, 9.4, 9.5, 9.6, 9.7, 9.8, 9.9, 10.0