TLILY 6 Pcs Step Drill Bit Set Titanium HSS Unibit Bits From 1/8 Inch to 1-3/8 Stepped Up & Center Punch

[HSS titanium coated bit set] High speed steel and titanium coating excellent durability and sharpness, reduce friction and make operation cooler. [Ultra automatic center drilling] Do you know that when you try to drill into metal or hard , no matter how stable you think it is, the drill will "walk"? Yes, we have a tool. The automatic center punch has a heavy spring effect. You only need to place the tip where you want to drill, and it will make a slight indentation on the . Enough to keep the drill bit from moving [118 ° separation point] These step drills have a small angle of 118 °, which can the cutting speed and prevent the inclined walking away from the center. Double groove design provides smoother cutting and removal [Double groove and three flat bits] These bits have special double groove straight design, reliable performance and durability. The shank of these step drills has three planes, which help prevent the drill bit from sliding in the drill chuck during drilling [Drill