Metric M42 8% Cobalt Twist Drill Bits Set for Stainless Steel and Hard Metal (1mm-10mm/19pcs) - -

Description

The research shows that HSS with cobalt has a higher temperature resistance and Red hardness, a greater wear resistance(Hardness) and a higher heat treat response than HSS without cobalt . Red hardness, it causes the hardened steel to have an ability to maintain hardness at approximately 860-880 ℃. Higher Tempering resistance,it means to maintain a high hardness at high temperatures for an extended period of time. 68-70 HRC,it means that the drill bits has 3X cutting ability and 2X durability. This drill bits set is made of Premium Cobalt (80,000 dollars per ton). This drill bits set is made of Premium Cobalt (80,000 dollars per ton). Holds up better than generic high-speed steel,8% Cobalt gives high-speed steel more heat and wear resistance. 3 Steps desigh tip starts drilling immediately with less force and eliminates "walking" across the work surface. Ideal for Stainless steel and Hardmetal,Hardwood,Aluminum,Copper,Plastic and Hardwood. Suitable for drilling Stainless Steel,Hard Metals,Aluminum,Copper,Plastic and Hardwood. The 3 steps design makes it accurately centered for woodworking jobs that require precision drilling. Also, the cobalt-containing design makes it perform even better in hardwood drilling. Non-vertical use may cause the drill bit to break. Using a drill press with sufficient power will make drilling easier. Do not use the drill bit on a percussion drill. This Drill bit can not be used on glass, walls and concrete. A high RPM does not improve drilling efficiency, but rather increases the heat between the bit and the workpiece, which may cause the bit to soften and the workpiece to harden. Drill diameter≤5mm，RPM（1000~700） 5-10mm，RPM（700~350） 10-15mm，RPM（350~200） Add stainless steel tapping oil or engine oil to prevent the stainless steel from overheating and forming a very hard oxide layer. It also works adding some vinegar,soy sauce or water if you don't have engine oil.

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