Abstract: A lubricant dispenser for a viscous lubricant such as grease, for a chuck body of a power chuck, comprises a container for containing a supply of the viscous lubricant. A delivery plunger, which is in the container and acts on the lubricant, is continually subjected to the pressure of a pressure medium. This forces lubricant from the container into a flexible line which is connected to a pressure intensifier mounted on the chuck body. The pressure intensifier contains a pressure piston which is movable under the influence of an intermittently operating pressure medium, and which carries a displacement piston which can be engaged against a receiving insert of the chuck body to open a valve and close the discharge of lubricant from the pressure intensifier into the chuck body.