How To Master The Grinding Scale Of Straight Shank Fried Dough Twists?

The straight shank Fried Dough Twist drill is a commonly used drilling tool. It has a simple structure and is easy to sharpen. Sharpening the drill bit properly is crucial for the processing of workpieces, but it is not an easy task to achieve perfect sharpening. The key lies in mastering the methods and techniques of sharpening. Once the methods are mastered, coupled with experience from multiple sharpening attempts, one can achieve a good grasp of the sharpening scale for the drill bit.
How to master the grinding scale of straight shank Fried Dough Twists?
Before sharpening the drill bit, it is necessary to first place the main cutting edge of the drill bit and the grinding wheel surface on a horizontal plane. In other words, ensure that the entire cutting edge is ground when it contacts the grinding wheel surface. This is the first step in positioning the drill bit and grinding wheel relative to each other. Once the position is set, gradually bring the drill bit closer to the grinding wheel surface.
2. This angle refers to the cutting edge angle of the drill bit. If the angle is incorrect at this point, it will directly affect the size of the drill bit's vertex angle, as well as the shape of the main cutting edge and the inclination angle of the chisel edge. Here, it refers to the positional relationship between the axis of the drill bit and the surface of the grinding wheel. A 60° angle is suitable, as this angle is generally more accurate to measure. It is important to pay attention to both the relative horizontal position and angular position of the drill bit before grinding. The two should be considered comprehensively, and one should not neglect the angular positioning for the sake of leveling the cutting edge, or neglect the leveling of the cutting edge for the sake of achieving the correct angular positioning.
3. After the cutting edge contacts the grinding wheel, it should be ground from the main cutting edge towards the back. That is, the cutting edge of the drill bit should first come into contact with the grinding wheel, and then slowly grind down along the entire rear cutting surface. When the drill bit cuts in, it can gently touch the grinding wheel, initially performing a small amount of grinding. Pay attention to the uniformity of the sparks, adjust the pressure on your hand in a timely manner, and also pay attention to the cooling of the drill bit. Do not let it overheat, causing the cutting edge to change color and even undergo annealing. If the cutting edge temperature is found to be high, the drill bit should be cooled promptly.
4. This is a standard drill grinding action. The main cutting edge should swing up and down on the grinding wheel, which means the hand holding the front of the drill should evenly swing the drill up and down on the grinding wheel surface. However, the hand holding the handle should not swing, and it is necessary to prevent the rear handle from tilting upwards. That is, the tail of the drill should not be tilted higher than the horizontal centerline of the grinding wheel, otherwise the cutting edge will become blunt and unable to cut. This is the most crucial step, as the quality of the drill grinding is largely related to it. When the grinding is almost complete, start from the cutting edge and gently rub it towards the back corner to make the back of the cutting edge smoother.