For solving the problem of drill breakage and increasing productivity, a built-in adaptive drilling control scheme has been proposed. The torque of the spindle detected using a floating torque measuring mechanism has been regulated by controlling the feed rate of the spindle using PID control algorithm. The adaptive control algorithm has been integrated into a numerical controller. Motor control functions are performed in a timer interrupt subroutine to realize real-time parallel processing. An experimental system has been established. Experiments have demonstrated that the system is applicable in preventing drill breakage and increasing productivity.