in use, the part to be held is inserted into the collet and then the collet is pressed (using a threaded nose cap) or drawn (using a threaded drawbar) into the body which has a conjugate taper form. the taper geometry serves to translate a portion of the axial drawing force into a radial clamping force. when properly tightened, enough force is applied to securely clamp the workpiece or tool. the cap or drawbar threads act as a screw lever, and this leverage is compounded by the taper, such that a modest torque on the screw produces an enormous clamping force.