8 Pieces Wood Countersink Set: 4 standard countersinks and 4 four-flute chamfering countersinks, can be used with bench drill, hand drill or other professional drilling machine. To avoid slippage or eccentricity during drilling, we recommend using a bench drill or fixing the drill. [7 Countersink Drill Bits for Wood] Made of high quality carbon steel with titanium coating, the drilling length can be adjusted for different lengths of , the chamfer is 5 flutes which can discharge the wood faster when using. 6 Pieces 1/4" 90 Degree Hexagonal Countersink Drill Bit Set - Made of standard high speed steel. With high frequency quenching for heat treatment, HSS countersink drill bits have high toughness and hardness. Titanium coated, the chamfer kit is rust-proof and has a long 3 Pcs Step Countersink Drill Bit Set: Forged from titanium coated high-speed steel, the hexagonal shank of the step drill bits adopts a grooved design, helps the electric drill clamp more firmly, suitable for drilling