The actuator holds the clamp ribs in a pocketed slot that allows them to move axially when being expanded and the spirally wound spring secures them to the mandrels tapered groove. These attributes allows the clamp ribs to expand smoothly and evenly when locking the tool to the i.d. and just as importantly they also contain them when the tool is released from the tube i.d. and holds them in place for the next clamping cycle.