Rotary torque gauge, idler & recording systems are designed to give an indication of various down hold conditions, thus warning the driller of locked cones, dull bit and stress on the drill pipe. It should be set to zero while the drill stem is rotated at normal operation speeds off bottom. As weight is applied to the bit, the resultant increase is the actual measurement of drilling torque. The sensing unit (idler assembly) is installed under the bottom side of the rotary chain. This assembly acts as a lever. As torque is built up, the rotary chain becomes tighter and presses down upon the wheel turning the idler frame. As a result, there is an increase in hydraulic pressure within the cylinder. This pressure signal is carried from the cylinder through high-pressure host to the dial indicating gauge mounted in front of the driller.