Bone drilling procedures are frequently performed in various surgical fields using computed tomography. The robotic systems employed to perform such procedures can improve the targeting accuracy and reduce the radiation exposure to surgeons. This report presents the mechanism, navigation system, and experimental evaluation of a proposed robotic drilling system. This system provides automatic drill tip alignment and target drilling. Unlike previously proposed robotic drilling systems, the system developed here employs a drilling mechanism based on rolling friction and an orientation mechanism using a four-bar linkage with a linear actuator. It also implements a release mechanism between the robot and drill to enhance surgical safety. The proposed orientation mechanism was proven to provide a high drilling location accuracy. To guide the robot and enable automatic target drilling, we developed a vision-guided navigation system, which was integrated with the proposed robot using a stereo camera. The effectiveness of the proposed robotic system was demonstrated by performing ex vivo drilling on swine femur samples.