1. Two tip dial

The advantage of two tip positioning is correct and reliable centering, and convenient installation. Mainly used for machining parts with high precision requirements. The top function is to center the workpiece and bear the weight and cutting force of the workpiece. The top is divided into front top and back top.

When clamping a workpiece with two tips, the installation is as follows: first use a split chuck or a chicken heart chuck to clamp the circumference of one end of the workpiece, then screw the lever into a three jaw chuck and extend the lever towards the end face of the split chuck or chicken heart chuck. When the lathe spindle rotates, it drives the three jaw chuck to rotate, which then drives the lever to rotate simultaneously. The lever moves the split chuck or chicken heart chuck, and the workpiece rotates with the rotation of the three jaw chuck. The two tips only have a centering and supporting effect on the workpiece, and the workpiece must be driven to rotate by the lever of the split chuck or the chicken heart chuck.

Precautions when using two tips to clamp workpieces:

(1) The connection between the front and rear centers should be coaxial with the centerline of the lathe spindle, otherwise there will be unnecessary taper errors.

(2) The tailstock sleeve should be extended as short as possible without interference with the turning tool to increase rigidity and reduce vibration.

(3) The shape of the center hole should be correct and the surface roughness should be good.

(4) The fit between the two top center holes should be appropriately tightened.

2. Top that can be moved

There are two commonly used shifting centers in turning machining: inner and outer shifting centers, and end face shifting centers.

(1) Move the top inward and outward

This type of top tapered tooth can be embedded into the workpiece and rotate it.

(2) End face shifting center

This top type uses end face claws to drive the workpiece to rotate, which is suitable for clamping the workpiece with a diameter of ф 50mm~ ф Between 150mm.