(1)\n3 Steps desigh tip starts drilling immediately with less force and eliminates 'walking' across the work surface.\n(2) Holds up better than generic high-speed steel,\nCobalt gives high-speed steel more heat and wear resistance.\n(3) This drill bits set is made of\nPremium Cobalt (80,000 dollars per ton).\n(4) The M42 metric cobalt drill bits can cut through Stainless steel and Hard metal,Hard wood, although they can be used for softer materials such as Aluminum,Plastic.\n\nSome Important Tips about\ndrilling stainless steel and hard metal:\n (1)Controling the drill speed from 200 to 1000 RPM would make it easier for you to drill holes on stainless steel.\n ________________________________\n Stainless Steel \n ____________________________\n Drill diameter RPM \n ____________________________\n 5mm 1000~700\n ____________________________\n 5-10mm 700~350\n ____________________________\n 10-15mm 350~200\n________________________________\n\n (2)Add stainless steel tapping oil or engin.