What Is a Live Center?
A live center is a device attached to the tailstock of a lathe to hold a workpiece. The main difference between a rotary center and a fixed center is that the rotary center has a bearing built into the body.
Live centers can only be used for a limited number of workpieces and revolutions because friction is generated between the fixed center and the workpiece as it rotates. This may cause unacceptable damage to the workpiece. Live centers, on the other hand, can hold the workpiece stable while interlocking with the workpiece and can handle high-speed rotation.
Uses of Live Centers
When machining with a lathe, if the workpiece is too long or the chucking area is too small, the spindle rotation and machining load may deform the workpiece, resulting in unstable machining. To solve these problems, live centers support the workpiece from the opposite direction of the chuck.
Live centers can hold the workpiece in conjunction with the spindle because bearings are built into the body of the center. On the other hand, the bearing has the disadvantage of increasing the diameter of the head. When a tool is close to the live center, it is necessary to pay close attention to the interference with the live center.
Principle of Live Centers
Live centers are mounted on the headstock of a lathe. The shank is generally a Morse taper shank that fits the shaft size of the tailstock.
Live centers can be roughly divided into two types.
- Umbrella Type Live Center
The tip of the rotary center is shaped like an umbrella. They are used as centers when processing hollow pipe materials. - Lace Center
This is a general live center used as a runout stop when machining bars and blanks on a lathe. The all-steel type, in which the main body is made entirely of the same steel, is the most common type, but there are also types with carbide tips on the tip. Depending on the material of the workpiece, the tip may be damaged by abrasion, so the type with a carbide tip is suitable when higher hardness is required.
Recently, a tip-replaceable type has also become available. This type has a separate live center body and center head. Replacing the center head, there are many advantages, such as easy replacement with a new one and compatibility with a variety of workpieces.