Rotary live centre

ROTATING TAILSTOCKS FOR DIFFERENT APPLICATIONS

To optimize the choice of a rotary tailstock, bear in mind that its function mainly consists in keeping the piece in axis during machining, preventing it from rotating off axis, causing vibrations, turning with roundness errors, surface with excessive roughness, short life of the tool that performs the machining. But the reason that makes it more important in its use consists in preventing the piece from swinging from its center until it comes out of the chuck jaws, therefore without control it can cause damage to the machine tool, but even worse the piece out of control can hit and seriously injure the operator on board the machine.

How to choose a rotary tailstock for the lathe

Rotary tailstocks must be chosen according to the following parameters:

- Type of shank or attachment

- Mass of the piece

- Rotation of the piece during machining

- Precision cylindricity of the piece

- Precision roundness of the piece

- Quantity of pieces to be produced

- In case of difficult pieces and long shafts, choose whether it should also be used as a drag

- Choice of the correct tip based on the size of the tool

Preparation of the piece for the insertion of the rotating tailstock

- Drill a hole with a center bit having a countersink angle equal to the angle we used for the cusp

- If it is inserted in a hole, choose the cusp based on the chamfer created at the beginning of the hole

Scheduled maintenance of the rotating tailstock

Live centers should still be checked between uses for radial or axial play in the precision bearings. When replacing the bearings, also replace any axial compensation springs.

Rotary centers are essential tools in the turning process, primarily used to keep the workpiece aligned during machining and to prevent it from rotating out of axis. This device is crucial in preventing vibrations, reducing roundness errors, ensuring a surface without excessive roughness, and extending the life of the cutting tool. The primary function of the rotary center is to prevent the workpiece from oscillating out of its center, which could result in it coming loose from the chuck jaws. Such an event can not only damage the machine tool but also pose a serious hazard to the operator.

Rotary centers must be carefully selected based on parameters such as the type of shank or attachment, the mass and rotation of the workpiece, the precision of the workpiece’s cylindrical and roundness accuracy, and the quantity of parts to be produced. It is particularly important to choose the correct tip based on the tool's footprint and to assess whether the center should also be used for driving, especially in the case of difficult workpieces and long shafts.

An example of a rotary center is one with a cylindrical shank without compression, ideal for single and multi-spindle lathes. This center can be equipped with a profiled or extended tip and is often chosen for its ability to maintain high precision during machining. Preparing the workpiece requires drilling with a center drill, where the countersinking angle must match the tip's angle. Additionally, it is essential to perform scheduled maintenance on the rotary center, checking the radial or axial play of the precision bearings and replacing the axial compensation springs if necessary.