Geometric features can be divided into the following three parts.
Length
The ratio of length to diameter is called magnification, and the smaller the magnification, the better the rigidity. Choosing a drill bit with just the blade length and the shortest suspension length can improve the rigidity of machining, thus improving the service life of the tool. The blade is not long enough to damage the drill bit.
Tip Angle
The drill tip angle of 118° may be the most common in processing, and is usually used to process soft metals such as low-carbon steel and aluminum. This angle design usually does not have a self-centric function, which means that it is inevitable to process the centering hole first. The 135° drill tip angle usually has a self-centric function. Since there is no need to process the centring holes, this will make drilling the centring hole alone no longer a necessary process, thus saving a lot of time.
Spiral angle
For most materials, the spiral angle of 30° is a very good choice. However, for environments that require better chip removal and higher cutting edge strength, you can choose a drill bit with a smaller spiral angle. For materials that are difficult to process, such as stainless steel, you can choose a design with a larger spiral angle to transfer torque.
