Plane drill is widely used in many factories and enterprises in our country, because it has the advantages that the general drilling machine does not have. For example, it is easy to operate, flexible, widely applicable and typical. As a common machine tool, there are some problems in operation. When the bit is broken, the main reasons are as follows: < br style = "list style type: none;" / > 1. The drill bit is blunt, but drilling is still going on. < br style = "list style type: none;" / > 2. The spiral groove of the drill bit is blocked by chips and the chips are not discharged in time. < br style = "list style type: none;" / > 3. When the hole is fast drilled through, the feed rate is not reduced or the machine is changed to manual feed. When drilling brass soft metals, the back angle of the bit is too large and the front angle is not grinded, resulting in the automatic rotation of the bit. < br style = "list style type: none;" / > 5. The grinding edge is too sharp, resulting in the phenomenon of chipping, but the tool can not be withdrawn quickly. < br style = "list style type: none;" / > the effective method to avoid bit breakage: < br style = "list style type: none;" / > (1) before drilling, the end face of the workpiece shall be flattened, and there shall be no convex head left at the center, and the drill bit shall be installed in the tailstock sleeve to align the drill axis with the workpiece rotation axis. (2) in order to prevent the bit from radial runout, a block iron can be added on the tool holder to support the head of the bit and help the bit to center. When drilling small and deep holes, the center drill should be used to drill the center hole first, so as to avoid the hole deviation. In the process of drilling, the drill bit is often withdrawn to remove iron chipping. (4) when the drill bit is just in contact with the end face of the workpiece and the through hole is about to drill through the workpiece, the feed rate will slow down due to the increase of the axial resistance due to the first penetration of the cross edge. During the drilling process, it is necessary to pay attention to frequent back drilling and timely lift up the bit. At the same time, it can also take the opportunity to input coolant or cool in air. By using the above method, the breakage of drill bit can be reduced, so as to save material, improve production efficiency and improve the processing quality of workpiece. In order to reduce the cutting temperature, reduce the friction coefficient between chip, workpiece and tool contact surface, and achieve the purpose of improving the service life of the small-diameter drill bit, transparent antirust water is generally used as the coolant for sufficient cooling. In addition, a layer of molybdenum disulfide can be coated on the groove of the drill bit, or lubricating with low viscosity mechanical oil or vegetable oil can be obtained. To sum up, in order to obtain satisfactory drilling effect, plane drill bit should pay attention to the above aspects in the use process, and the technical measures adopted should be changed accordingly due to the limitations of workpiece material, quality requirements and drilling position.