Ideal for drilling large and small-diameter holes in stainless steel and plastic plates. The HSS M35 cobalt Co. coated allows for fast, accurate starts that generate less heat, resulting in longer bit tip life. Cobalt coating increase the step drill hardness to HRC 65-67, enhances durability, whole quality and bit life. For user convenience and accuracy, each bit has laser-engraved reference marks you can see while drilling. The spiral grooved flutes ensures faster & jam-free drilling. Hex shank with raised bump stands more torque and won't break when drilling big sizes, suits quick change adaptors ensures a solid connection with the drill chuck.

CNC machine manufactured with high accurate size and shape 

CBN grinding wheel milled, smooth and shinning.

6.35mm hex shank

5mm step height

Each piece packed in transparent plastic box

4-32mm with 15 steps: 4,6,8,10,12,14,16,18,20,22,24,26,28,30,32mm