Abstract: The present invention is an improved apparatus for controlling the weight on the drill bit during operation. In this invention, an inner mandrel has a telescoping movement in response to added drill string length at the surface. As the inner mandrel telescopes closed, it approaches a restrictor which is fixedly disposed in the lower housing of the drill string assembly. When the inner mandrel mates with the restrictor, a stand-pipe pressure increase noticeable to the operator occurs. The operator then stops the drill string and allows the motor to drill ahead. As the motor drills ahead, the inner mandrel telescopes open and the operation is then repeated.