How to control the quality of hardware drilling?

If the drill bit is not polished for a long time, the cutting edges on both sides of the drill bit will be worn, and the sizes of holes drilled will be different. After the bit is worn, it is easy to squeeze the bit too hard, and the drilling will not be rounded into hexagon, ellipse or eccentricity. The service life of the drill bit is not determined by time, but depends on the quality and feel of the drill bit. When the drill bit is worn, it feels different. If you don't wear it, it will deform! If the material is excellent, it is recommended to use titanium drill, which is durable and not easy to wear!