The EOD robot is a mobile robot used in replace of a human in explosive ordnance disposal operations of searching, detecting and handling of explosive materials. Nowadays the EOD robot.s tool capabilities and overall performances are at lower levels because they are only able to use one kind of tool (gripper) for the whole bomb disposing process. The aim of this study is to design a completely mechanical quick changeable joint which will be used in the EOD robot to automatically change the tools. By changing the grippers automatically, the robot firstly does not require to be called back for tool change and secondly can achieve different operations on the explosive material. In the locking mechanism of quick changeable joint, hydraulic and pneumatic systems are not preferred because of their weight and volume on a mobile robot. Electromagnetic locking systems are also not considered because of possible electromagnetic interaction between the arm and explosive ordnance. The reason of designing a completely mechanical joint is to eliminate the use of another actuator for controlling the locking mechanism. An EOD robot with a quick changeable joint will be able to use different tools and accomplish complex tasks by using these different tools. Usage of this quick changeable joint in different robotic applications such as tool holding in CNC machines, lifting and pulling applications will also make an increment in the robot.s processing capacity and efficiency. This project consists of designing a completely mechanical quick changeable joint. In order to understand the best design, four different joints are designed, the critical parts are analyzed for strength and prototypes of the joints are manufactured. To test the life cycles of the joints a pneumatic test machine is designed and manufactured. After the tests, the joints are evaluated for design parameters are the best design for different purposes are determined.