Abstract: An improved locking tool having a toggle mechanism extending between the operating handles has a cam located at an intersection of two of the elements of the toggle to vary the distance between the points of contact between the mechanism and the handles as the tool is opened or closed. The adjustment to such distance provides for increased ease of operation with less operating force. Disclosed embodiments include a further mechanism to assist in the separation of the handles and to resealably lock the handles in the clamped position.