There are several disadvantages to the twist drill:
(1) the internal and external difference of the front Angle values of the points on the main Cutting Edge of standard twist drill is too large. The front Angle of the main cutting edge at the outer edge of the bit is about +30; The front Angle near the core is about -30.
Close to the front Angle of the drill center is too small, causing the chip to deform large, the cutting resistance is large; Near the outer edge of the anterior horn is too large, in processing hard materials, the strength of the cutting edge is often insufficient.
(2) the transverse edge is long, and the front Angle of the transverse edge is a large negative value, which is -5 4°～-6 0°, which will produce a large axial force.
(3) compared with other types of cutting tools, the main cutting edge of standard twist drill is very long, which is not good for cutting and cutting.
(4) take place after the deputy vice cutting edge of blade Angle is zero value, cause vice knife after the friction between the surface and hole wall, cutting temperature rise, the outer edge of the corner of bit wear is bigger, has processing surface roughness.
The above defects often make the drill wear fast, seriously affecting the drilling efficiency and the improved surface quality.
What should you do when your twist drill bit is dull?
If the twist drill bit is dull, do you throw it away?
Don’t throw it away, you can buy twist drill bit sharpener to repair it, the blunt bit after repeated grinding can be used. In terms of cost, the amount of money you save will be enough for you to buy a drill sharpening machine. We are the drill bit grinder manufacturer. If you buy the drill bit grinding machine in bulk, our price is more advantageous. Welcome to know the details.