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About twist drill composition concept
- Jan 09, 2018 -

Twist drills are tools that cut through the circular holes of a workpiece by their rotation relative to the fixed axis. Because of its chip flute into a spiral shaped like twist and got its name. Twist drills are tools that cut through the circular holes of a workpiece by their rotation relative to the fixed axis. Because of its chip flute into a spiral shaped like twist and got its name. Spiral groove has 2 slots, 3 slots or more slots, but the most common 2 slots.

The diameter of the twist drill is limited by the aperture, the spiral groove makes the drill core thinner and the rigidity of the drill bit low; only two strip guides are orientated, the axis of the hole is easy to deflect; the chisel edge makes the centering difficult and the axial resistance increases, Easy to swing. Therefore, the drilled hole shape error is larger. The rake face and flank face of the twist drill are curved surfaces. The rake angles and the relief angles along the major cutting edges are all different. The rake angle of the rake edge reaches -55 °. Cutting conditions are poor; cutting speed distribution along the cutting edge is unreasonable, the lowest intensity cutting tip cutting speed, so wear serious.