1. The three-claw chuck is the most commonly used universal lathe fixture. The biggest advantage of the three-claw chuck is that it can automatically center, has a large clamping range, and has fast clamping speed, but the centering accuracy is still there. Error, it is not suitable for secondary clamping of workpieces with high coaxiality requirements. 2. In order to prevent the deformation and vibration of the workpiece from affecting the processing quality during turning, when the workpiece is clamped in the three-jaw self-centering chuck, its overhang length should not be too long. For example: if the workpiece diameter is ≤30mm, its overhang length should not be greater than 3 times the diameter; if the workpiece diameter is >30mm, its overhang length should not be greater than 4 times the diameter. At the same time, it can also prevent the workpiece from being bent or dropped by the turning tool, causing cutting accidents. Three-claw self-centering chuck: Use a voltaic wrench to rotate the bevel gear. The bevel gear drives the flat rectangular thread, and then drives the three claws to move centripetally. Because the pitch of the flat rectangular thread is equal, the three claws move at the same distance, and there is automatic centering. role. 1 Loosen the three positioning screws and take out the three small bevel gears 2 Loosen the three fastening screws and take out the dust cover and the large bevel gear with flat threads 3 When installing the chuck, use the square tenon of the chuck wrench Insert into the square hole of the small bevel gear and rotate, driving the plane thread of the large bevel gear to rotate. When the screw thread of the flat thread is turned to be close to the housing groove, install the No. 1 catch into the housing groove. The remaining two cards are loaded in the order of No. 2 and No. 3. The installation method is the same as before