Tin-Coated Twist Drill Bit Set 19PCS Set

Twist drill is the most widely used machining tool. The usual diameter range is 0.25 to 80 mm. It is mainly composed of bit working part and shank. The working part has two spiral grooves, shaped like a twist, hence the name. In order to reduce the friction between the guide part and the hole wall when drilling, twist drill from the drill tip to the handle direction gradually reduce the diameter of the inverted cone. The screw Angle of twist drill mainly affects the size of cutting edge Angle, edge edge strength and chip removal performance, which is usually 25° ~ 32°. Spiral grooves can be processed by milling, grinding, hot rolling or hot extrusion, and the front end of the drill bit forms a cutting part after grinding. The cutting Angle of the standard twist drill is 118, the bevel Angle of the cross edge is 40° ~ 60°, and the back Angle is 8° ~ 20°. Due to structural reasons, the rake Angle is large at the outer edge and gradually decreases to the middle, and the transverse edge is negative rake Angle (up to about -55°), which acts as extrusion when drilling.

Welcome to Behappy Crafts, we are a professional manufacturer of power tool accessories, we are specilized in various cutting tools and tool set, drill bits, hole saw, cutting discs, etc. Our Twsit drill bits are exported to many countries all over the world. We produce HSS twsit drill bits for metal working, carbon steel drill bits for wood working, and also masonary drill bits for concrete works. We provide OEM if you have large quantity, custom the twist drill bits as customers' request. We can produce various sets include different size in metric and inch. Welcome to visit Behappy Crafts and hope we can start our cooperation in the future. 

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