3 Pieces High Speed Steel Straight Groove Step Drill

Features: 100%  and High Quality Made of High Quality HSS Steel Ideal for cutting holes in a variety of materials, including steel, brass, wood, plastic, and more. Titanium coating to reduce heat Heat treated and highly polished. Drill round holes perfectly in steel, brass, plastic, wood, etc. 3-sided shank design to prevent slippage in the chuck Two-flute design drives faster, smoother and cleaner cuts each step is clearly labeled with depth diameter by steps Function: Deburring, chamfering, cutting or expanding holes Support Tools: G un Drill, Hand Drill, Load Drill, Bench Drill. (Cooling by water injection during working, it can effectively extend the service life of the drill bit, especially in the case of continuous drilling) Rotation speed: 4-12 speed: 260-400 4-20 Speed: 180-240 Attention: Due to the outer diameter of each stage of the step drill is gradually expanded, the corresponding cutting strength and linear speed will also be gradually increased. Since the step drill is completely dependent on the angled edge, which is only 1mm in length, si le speed feeding is too fast when drilling, it will be easily caused by the abrasion of the oblique edge. Please exert downward force when drilling, do not press too hard to avoid edge wear. Suitable material: general hardness parts, such as wood, plastic, PVC plate, iron plate, plate thickness less than 3MM. Please note that stainless steel and spring steel are not applicable. Not for tempering. Length: Length 3-12mm: approx. 7.9cm/ 3.11" Length 4-12mm: approx. 6.7cm/ 2.64" Length 4-20mm: approx. 7.4cm/ 2.91" The k niv es are available  in The following sizes: 3-12mm(3mm,4mm,5mm,6mm,7mm,8mm,9mm,10mm,11mm,12mm) 10 steps 4-12mm: (4mm, 6mm, 8mm, 10mm, 12mm) 5 steps 4-20mm :(4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm)9 steps