If the spindle headstock of the lathe is disassembled and found to be seriously worn at the rear bearing lock nut of the spindle, it should not be used. Students should be instructed to compare several schemes and combine their own experience in maintenance work to determine the repair scheme for the shaft: The original M74×1.5 at the thread is changed to M72×1.5 standard thread, and the nut is re-equipped. In the repair of worn parts, if the parts can be repaired with a fitter, it is necessary to guide the students to operate so that the students' operations are more accurate and efficient. If the gear is toothed or worn, the student should be instructed to replace it. In the repair of the bushing shaving, pendulum and thread, the initial repair operation can guide the students to do it themselves, and finally the repair teacher can personally carry out and guide the students to gradually master the operating essentials and operation skills. The key to troubleshooting the “analysis guide†for troubleshooting the machine is to analyze and determine where the fault occurred and the cause. The specific method of guiding analysis is to "listen", that is, to listen carefully to the sound of the machine running, and to judge the running state of the machine by the sound of the machine. Teachers should explain clearly to students and help them gradually increase their experience to meet the needs of practical work. "Check", that is, the inspection of the machine. Whether the position of each component is adapted, whether the adjustment member is adjusted, and whether the gear shifting operation mechanism is in place. Whether the tight parts such as nuts, bolts, and pins are tight. "Look", that is, starting from the assembly drawing and the transmission system, carefully reviewing the drawings, analyzing and researching the transmission system step by step to determine the cause of the failure. It can also be combined with the processing quality of the machined parts to analyze and indirectly determine the parts and causes of the machine tool failure. In the repair of the lathe headstock, in order to cultivate students' ability to analyze faults. The author intentionally set up several faults, let the students analyze the cause of the fault and eliminate it. For example, the following faults are set for the I-axis friction clutch and the operating mechanism: 1 The power of the turning workpiece is small, and the workpiece cannot be driven when turning. 2 The clutch handle is lowered by itself when turning. 3 Spindle rotation has positive rotation without reversal. The following faults are set in the spindle adjustment: 1 When the workpiece is turned, the workpiece has a dull pattern and the surface roughness is low. 2 The spindle of the machine tool rotates and the spindle bearing heats up. After the fault is set, the students are required to seriously think and judge. List the possible causes of the failure and propose solutions. On this basis, the students are instructed to manually troubleshoot the fault. In short, in the integrated teaching of mechanics and fitters, it is necessary to fully mobilize the students' "enthusiasm" and give full play to the students' "activeness", so that they are proficient in the operation skills of disassembly, repair and assembly of machine tools and apply them to practice. (Finish) Control Valve,Pipe Fitting,Wcb Y-Strainers Baoding Valvula Imp & Exp Trading Co., Ltd. , http://www.hbvalves.com