When using common access pole twist drill hole, pouring opposite direction of the chips and coolant discharge direction, hindering the cutting fluid into the cutting edge, high cutting temperatures cause coolant vaporized coolant penetration and therefore less (4 -6) d0 or more deep, forming dry cutting. Twist Drill hole coolant can be directly injected into the cutting edge portion, which can reduce the cutting temperature, reducing blade wear and improve production efficiency. For high hardness, stainless steel and other difficult to cut materials as well as I was drilling its advantages more prominent.
　　Another feature is that the twist drill hole by increasing the pressure of the coolant, to achieve the purpose of forcing chip. Workpiece material, tool material. Drill diameter and speeds under exactly the same circumstances, only changing the feed amount of test drilling, twist drill hole in order to obtain a torque than the average small twist, drilling depth deeper than ordinary twist drill, drilling efficiency ratio ordinary high twist.