Solid Carbide DrillsHolemaking Solid Carbide Drills Deep Hole Drilling Application Guide 1 Short drill for piloting Coolant : On/off 3×D ~ 5×D Drills 2×D 2 Long drill into pilot hole Coolant : Off 10xD ~ 20xD Drills n = 100~500rpm 1.5×D Vf > 500mm/min 3 Spotting Coolant : On 10xD ~ 20xD Drills Vc = 100% 3×D Vf = 50% 4 Deep Hole drilling Coolant : On 10xD ~ 20xD Drills Vc = 100% Vf = 100% 5 Retracting Coolant : Off 10xD ~ 20xD Drills n = 100~500rpm Vf > 500mm/min B046