The present work on adaptive control addresses deep drilling with single-lip drills of small diameter. This study develops methods for process identification that enable the safe identification and appropriate modeling of the current process behavior during deep drilling along the drilling path. To utilize the identification methods for optimal controller parameter adaptation, a controller design is developed that induces an optimal control behavior for small tool diameters. The control behavior initially includes a rapid response to large deviations and subsequently adopts a more conservative approach to prevent overshooting of the controlled variable. This controller design shows significant advantages in terms of the quadratic control area and is suitable for production systems with pronounced dead time behavior.