Chuck installation and jaw removal of lathe

Chuck is a common accessory of ordinary lathes and is used to clamp workpieces. There are two types of chucks commonly used on lathes: three-jaw self-centering chucks and four-jaw single-action chucks.

The three jaws of the three-jaw self-centering chuck are evenly distributed around the chuck, and can move synchronously in the radial direction to realize the clamping or loosening of the workpiece, and can be automatically centered. Generally, there is no need to find when clamping the workpiece. Yes, easy to use. The clamping force of the three-jaw self-centering chuck is small, and it is suitable for clamping medium and small cylindrical, regular triangular or regular hexagonal workpieces. Commonly used three-jaw self-centering chuck specifications are 15omm, 2omm, 25omm, etc.

The four jaws of the four-jaw single-action chuck are evenly distributed along the circumference, and each jaw can move radially independently. When clamping the workpiece, the position of the workpiece can be corrected by adjusting the position of each jaw. The clamping force of the four-jaw single-action chuck is relatively large, but it is troublesome and time-consuming to correct the position of the workpiece. It is suitable for clamping non-circular workpieces in single-piece and small-batch production. The chuck is a common accessory of the military bed. It is used to clamp the workpiece. The operator must be familiar with the structure of the chuck and be able to disassemble, clean, lubricate and install the jaws skillfully.

1. The structure of the three-jaw self-centering chuck of ordinary lathe

Insert the square tenon of the chuck wrench into the square hole at the end of the small bevel gear, turn the wrench to rotate the small bevel gear and drive the large bevel gear to rotate. There is a plane thread on the back of the large bevel gear, which meshes with the end face thread of the claw. When the large bevel gear rotates, the plane thread drives the three claws engaged with it to move radially or centrifugally.

2. The loading and unloading of the three-jaw self-centering chuck jaws of ordinary lathes

(1) Jaw identification: The three-jaw self-centering chuck has two pairs of positive and negative jaws. The positive jaws are used to clamp workpieces with a smaller outer diameter and larger inner diameter, and the reverse jaws are used to clamp workpieces with a larger outer diameter. Each pair of claws is marked with numbers 1, 2, and 3, and the claws must be assembled in sequence when installing the claws.

(2) Jaw installation: insert the square tenon of the chuck wrench into the square hole on the cylindrical surface of the chuck shell. Rotate clockwise to drive the large bevel gear to rotate. When the turnbuckle of the flat thread on the back is close to slot 1, insert the No. 1 claw into slot 1 of the housing, and continue to rotate the chuck wrench clockwise. The No. 2 and No. 3 jaws are sequentially loaded into No. 2 and No. 3 slots of the chuck housing. As the chuck wrench continues to rotate, the three jaws move radially and centripetally until they converge on the center of the chuck.

(3) Disassembly of the jaws of ordinary lathes: Turn the chuck wrench counterclockwise, and the three jaws will move centrifugally along the radial direction synchronously until they exit the chuck shell. When the jaws withdraw from the chuck housing, care should be taken to prevent the jaws from falling and being damaged from the chuck housing.