Extremely Heat Resistant : twist drill bits Must be used and operated at 1500 RPM or greater for maximum efficiency. Straight shank allows for firmly holding and accurate centering, fit for standard drill chucks and regular round collet chucks No Center Punch Is Needed:The 135° Quick-Cut points are self-centering and penetrate quickly with less pressure. Twist drill bit kit Will not "walk" or "wander" Faster Cutting and Longer Life:Our Twist Drill Bit HSS are Manufactured from M35 cobalt steel, with molybdenum and cobalt added to creates a hardened alloy, measuring Rockwell hardness up to 67, for much faster cutting and extra longer life span, with up to 12 times when compared with an average HSS drill bit. Metal cutting range: thin metal plates (steel and aluminum) and body panels (metal, glass fiber and plastic), low carbon steel, they are very effective on these projects Easy Usage And Store :The set includes 13pcs of M35 cobalt steel twist drill bits: 1.5mm, 2mm, 2.5mm, 3mm, 3.2mm, 3.5mm, 4mm, 4.5mm, 4.8mm, 5mm, 5.5mm, 6mm, 6.5mm,13Pcs Packed in a Plastic Bag For Easy Usage And Store Product description High Speed Steel Surface, Titanium Coated. Good toughness of materials, wear resistance, drilling ability. Apply to: cast iron, copper, aluminum, plastic and wood. Extremely high hardness, in the drilling work has excellent processing performance,All grinding sharp ligament sticky milling work hole smooth no burr. Different types of drill bits are used to cut holes in different types of materials.Drill through metal like a champion Cobalt drill bits are not made of pure cobalt, but rather a steel alloy with certain percent cobalt. The 5-percent alloy is known as M35 grade. The cobalt increases the strength of the steel and makes it more heat-resistant; this is an important factor in drilling hard materials because the friction of metal against metal can produce high temperatures that damage the material or the drill bit. Tests shows that the M35 cobalt steel drill bits can penetrate a 5mm-thick 304 stainless steel plate in 5 seconds. Notice: The working life of the drill bits can be largely prolonged by using with cooling liquid. Speicifcations: Material: 95%high speed Steel+5%cobalt Feature:professional,Durable,For Wood, Plastic And Aluminum Ideal For DIY, Home And General Building/Engineering Using