The centre, which is accommodated in the main spindle sleeve, is known as a ‘live centre’ and the centre fixed in the tailstock spindle is known as a dead centre. In construction, both centres are identical, made as one unit that consists of a conical point of 60° included angle, a body provided with a Morse taper shank and a tang.
Though it is termed as half centre, little less than half is relieved at the tip portion. Used while facing the job without disturbing the setting.
The dead centre is made out of high carbon steel, hardened and ground whereas the live centre need not have its conical tip hardened as it revolves with the work. A good lubricant should be used for the dead centre.
The size of three-jaw chuck is specified by the diameter of the body of the chuck
The follower rest has usually two pads. One pad is located opposite to the cutting tool and the other pad bears the top of the workpiece to prevent it from springing up.