Step Drill Bits Set with Gradually Expanded Diameter for Easy Hole Cutting

Details:

* and

*Made from HSS steel

* for Ideal for using to holes in a variety of materials including steel, brass, wood, plastic, .

* coated to reduce mit and heat

*Heat treated and highly polished. Drills perfectly round holes in steel, brass, plastic, wood .

*3 sided shanks design in order to prevent slippage when in chuck

*Two for flute design drives faster, smoother and cleaner cuts each step is clearly labeled with the depth diameter in steps

*Function: Deburring, Chamfering, Cutting or expanding holes

*Supporting tools: Pistol drill, Hand drill, Charging drill, drill.(Water injection cooling while working, it can effectively extend the for service life of the drill , especially in the case of continuous drilling)

Package include: 1 x Drill Set 4-12 1 x Drill Set 4-20 1 x Drill Set 4-32 NO Bag

Attention:Because of the outer diameter of each step of the step drill is gradually expanded,then the corresponding cutting resistance and linear for velocity will also be gradually increased.

Owing to the step drill is completely dependent on the inclined edge that is only with 1mm length,If the feed is too fast when drilling,it will be easily to be annealing caused by abrasion of the oblique edge.

Please give a downward force when drilling, do not press down too hard to avoid the edge wearing.

Suitable material: Workpieces with for general hardness, such as wood, plastic, PVC plate, iron plate, plate thickness within 3MM. Please note that stainless steel and spring steel are not applicable. Not for quenching.(Water injection cooling while working, it can effectively extend the for service life of the drill , especially in the case of continuous drilling)