Manual resharpening method for twist drill bits

As one of the most widely used tools in industrial manufacturing, it is very common to resharpen twist drill bits after they have been worn out. Most of the factories that use twist drill bits are resharpening them by hand in the grinding machine due to the constraints. The following is the manual grinding method of twist drill bits.

1. "The edge is leveled against the wheel surface."

This is the first step in the relative position of the drill and the grinding wheel, there are often students who have not yet leveled the edge on the grinding wheel to start sharpening. This is definitely not good for grinding. The "edge" here is the main cutting edge, and "leveling" means that the main cutting edge of the part to be sharpened is in a horizontal position. The "wheel surface" refers to the surface of the grinding wheel. The word "leaning" means slowly leaning together. At this time, the drill bit cannot touch the grinding wheel.

2. "The drill shaft is placed diagonally out of the sharp angle."

Here refers to the relationship between the position of the drill axis and the surface of the grinding wheel. The "front angle" is half of the top angle of 118°±2o, about 60° This position is very important and directly affects the size of the top angle of the drill and the shape of the main cutting edge and the cross-edge bevel angle. To prompt students to remember the commonly used 30 °, 60 °, 90 ° triangle plate in the angle of 60 °, students can easily grasp. Recipe one and recipe two both refer to the relative position of the drill before sharpening, both should be integrated, do not ignore to set the bevel angle in order to set the edge, or to set the axis of beveling and ignore to set the edge. In actual operation, these mistakes are often made. At this time, the drill is ready to contact the grinding wheel with the correct position.

3. "Grind the back from the edge to the back."

This means to sharpen slowly along the entire back face of the drill from the edge of the bit. This facilitates heat dissipation and sharpening. On the basis of the stable consolidation of recipes one and two, at this time the drill can gently touch the grinding wheel and carry out a smaller amount of sharpening. When sharpening, observe the uniformity of sparks, adjust the pressure level in time and pay attention to the cooling of the drill. When re-starting sharpening after cooling, continue to set the position of the muzzle one and two, which is often not easy to grasp when learning for the first time, and often involuntarily change the correctness of its position.

4. "Swing the tail up and down don't cock."

This action is also very important in the sharpening process of the drill, often some novices in sharpening "up and down swing" into "up and down rotation", so that the other main blade of the drill is destroyed. At the same time, the end of the drill should not be high above the horizontal center line of the grinding wheel, otherwise the edge will be blunt and unable to cut.