Inch 21pcs HSS metal twist drill bit set

Twist drill is the most widely used hole machining tool. Typically, diameters range from 0.25 to 80 mm. It is mainly composed of drill bit working part and shank. The working section has two spiral grooves that look like a twist, hence the name. To reduce friction between the guide and the hole wall when drilling, the twist drill is gradually reduced to an inverted cone diameter from the tip of the bit to the shank. Twist drill screw Angle mainly affects the size of the front edge Angle, the strength of the blade and chip removal performance, usually 25° ~ 32°. Spiral grooves can be developed by milling, grinding, hot rolling or hot extrusion. The front end of the bit is grinded to form the cutting part. 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 the professional manufacturer of power tool accessories, we are specialized in drill bits, hole saw, cutting discs, etc. We produce various types of twsit drill bits, HSS4241, HSS4341, M35, M2, etc for metal working. Our Hss Co Twsit drill bits can be used to drill holes on stainless steels, fast working and dural to use. We can do the different surface treatment for the drill bits, like bright finish, tin coated, amber finish as per request.  We can also customize customers logos on the twist drill bits and package. So Weclome to visit us and start our cooperation soon. 

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