6 tips for sharpening a drill bit

Twist is a commonly used drilling tool, simple structure, the better it is important for the workpiece drill grinding, but make it really good sharpening, not an easy thing. The key is to master the methods and techniques of good sharpening, mastered the method, coupled with the experience of many grinding, it can be very good grasp drill sharpening scales.

Twist vertex is generally 118 °, it can also be viewed as 120 °. Sharpening drill can master the following six tips are generally not any problem.

1, before grinding drill, first drill main cutting edge and the wheel surface is placed in a horizontal plane, that is, to ensure that when the blade contacts the wheel surface to be ground to the whole blade. This is the first bit and the relative position of the wheel, the position in place before slowly to the surface by grinding wheel.

2, this angle is the angle of the front of the drill bit, then the angle is wrong, it will directly affect the apex angle drill size and shape of the main cutting edge and chisel edge bevel. Here is the location of the drill axis and the relationship between the wheel surface, taking 60 ° on the line, this angle is generally more able to see potential. Here we note that drill before sharpening the relative horizontal and angular positions, both to be balanced, not to settle gracefully ignoring the edge angle, or to settle gracefully angle while ignoring the edge.

3, edge grinding wheel after contact, from the main cutting edge to the back ground, that is, from the first bit of the edge came into contact with the wheel, and then slow down the mill along the entire flank. Contact drills gently cut the wheel, the first for a relatively small amount of sharpening, and to observe the uniformity of spark, and adjust the size of the hands of the pressure, but also pay attention to cool the drill bit can not be allowed to wear too much, causing discoloration edge , and to the edge annealing. Found that edge temperature is high, the drill must be promptly cooled.

4, which is a standard drill grinding operation, the main cutting edge to swing up and down on the wheel, i.e. the front hand grip portion of the drill bit to uniformly oscillate in the vertical surface of the grinding wheel. The hand grip portion can not swing, but also to prevent the handle to the upturned, that is not the tail Gao Qiao to drill horizontal center line above the wheel, otherwise it would blunt edge, can not be cut. This is the most critical step, bit worn, good or bad, and this has a great relationship. When worn almost from the beginning edge, angle and then gently rub back and let some of the back edge more smooth.

5, the side edge After grinding, then grinding the other side of the blade, the blade must be guaranteed in the middle of the bit axis, both sides of the cutting edge to symmetry. Experienced instructors will look at the light in front of the drill tip symmetry, proceed slowly grinding. After the drill cutting edge angle is generally 10 ° -14 °, after the angle is large, the cutting edge is too thin, powerful vibration when drilling, the orifice was triangular or pentagonal, needle-like chip; after a small angle, when drilling axial force is large, easy to cut, cutting force increases, large temperature rise, drill severe fever, not even drilling. Clearance angle grinding fit, spearpoint pair, edged symmetry, when drilling, drill chip light, no vibration, the aperture will not be expanded.

6, After two grinding of larger diameter drill bit grinding drill spearpoint Also note.

After grinding drill two, there will be a two-edged spearpoint at the plane, the impact drill centering, we need to look down the back of the blade angle to the plane of the blade tip grinding small as possible. The method is to drill upright alignment angle of the wheel, the roots behind the blade, blade tip facing down a slot. It is also important to set a brisk drill and cutting center point. Note that at the time of grinding the blade edge chamfering, do not grind to a main cutting edge, it would be the main cutting edge of the rake angle is too large, direct impact drilling.

Drill sharpening no certain formula, you need to accumulate experience in practice, by comparison, observation, trial and error, but with a certain intuition of the human body, in order to better grind drill