3Pcs Cobalt Step Drill Bits For Hard Metal, Metric M35 Unibit, 4-12,4-20,4-32Mm ?PREMIUM QUALITY?Crafted from M35 Cobalt High Speed Steel with cobalt and TiAlN coating, our step bits boast unparalleled toughness, high temperature threshold and long-term durability to consistently deliver exceptional results. ?IMPRESSIVE PERFORMANCE? With our special heat-treatment and quenching, the hardness of these bits are hardened up to 64-67 HRC. They are capable of drilling stainless steel and other high-performance alloys. The spiral flute design cuts through metal like a hot knife through butter, also the enlarged spiral flutes prevent chips from clogging and ejects chips rapidly. The tri-flat shank provides a stable grip with the drill and prevents breakage during drilling. ?VERSATILE APPLICATION?This set includes 3 step bits in varying sizes, with each of the 4-12MM, 4-20MM and 4-32MM. They are compatible for use with a range of drilling machines, table drills, milling machines, cordless drills, and electric drills. Ideal for drilling holes or expend holes in hard metal, stainless steel. Perfect tool for machinists, DIY enthusiasts, contractors, and homeowners. ?SAFETY PRECAUTIONS?For better results and longer life, it is best to apply cooling fluid when working with these bits and set your drill speed in the range of 250-400 RPM. It is not recommended to use impact drivers with these bits, the inconsistency of torque distribution in an impact can deliver bad results and potentially break the bit. ?MAKE EVERY PENNY COUNT!? No excessive packaging, this set contains everything you need and essential only. At ColumPRO, our value is to offer great products in the most cost-effective way. For our step bit set, you get 3 heavy-duty high quality step bits, each with a protective portable case for the individual bit and no redundant overpackaging box. The protective and portable case can be stored in your toolbox or workshop without taking up space.