3pc Hss step drill bit set cone hole metric 3/4 \- 12 / 20 mm 1 / 4 titanium coated core drill bits

This unique stepped structure allows a drill to open a variety of sizes and apertures a stepped drill can withstand a box of drill bits. Step drill can automatically deburr chamfer hole reaming twist drill can not complete the function it is possible. The two groove designs provide faster smoother and cleaner cutting with each step clearly marked with a step in the depth diameter. The material used is high-speed steel which has a longer service life and titanium plating reduces friction and heat making it more durable. There are three for a set of ladder drills that you can choose from and use in a wide range of applications. Specification: Color: gold. Material: HSS. Size: 4-12:69mm Size: 3-12:79mm Size: 4-20:73mm 1*4-12 step drill. 1*3-12 step drill. 1*4-20 step drill.