Intra-abdominal surgery has taken large steps away from the conventional method of open incisions in the last 2 decades. Minimally invasive methods have proven to be successful replacements in performing these surgeries. Recently, a newer approach known as natural orifice translumenal endoscopic surgery (NOTES) takes minimally invasive surgery further by eliminating external incisions and instead performs surgery via natural orifices such as the esophagus. NOTES concepts have been in existence during the past decade, but this approach is not widely adopted in human surgeries due mainly to the technological limitations imposed by such surgeries. In this paper, a new robotic platform for natural orifice surgery is described. The robot is designed to carry multiple tool tips in a single end-effector arm that is attached to a steerable and shape lockable drive mechanism. Tool changing capability is achieved by indexing the tool cartridge and advancing the tool of choice. The overall diameter of the robot is small enough for it to navigate through a human esophagus. The steerable and lockable drive mechanism allows easy navigation through the twists and turns of an orifice and also provides a stable platform for the robot while surgery is performed. Design and calculations are presented in this paper, followed by experimental validation. Initial results suggest that the new robotic tool will enable dexterous abdominal surgery with improved force transmission.