Abstract: A wrench having an adjustable jaw on a neck slidably supported by a guide on a handle with segmental threads on at least one side of the neck. An adjusting nut is threaded on the neck and has segmental threads rotatably and drivingly engagable with the threads on the neck. The threads on the neck are axially slidable between the ends of the segmental threads on the nut in at least one rotated position of the nut. A U-shaped spring has spaced arms which springably engage the opposite axial faces of the nut to confine the nut therebetween. The spring has a connecting bight which is nonrotatably opposed to wrench handle. The arms of the spring defining openings through which slidably and nonrotatably pass the neck.