Abstract: A bent pipe is made of a metal strip having one edge in a straight line and the other edge in a curved line by winding it helically. A double fold and a single fold are formed along the straight edge and the curved edge, respectively. Then the metal strip is wound helically so that the narrow portions will be in juxtaposition with one another.

Abstract: A machine vice comprises an elasticity-adjustment rod secured to and penetrating one of two vertical portions of a subtantially U-shaped stress-transmission frame such that the one end of the frame is in contact with a vice head having a stationary jaw and a guide rail, whereby the flexing and strain of the stationary jaw resulting when a work is clamped between the stationary and movable jaws is compensated for, thus ensuring the perpendicularity of the stationary jaw with respect to the guide rail top surface and parallelness of the two jaws.

Abstract: A machine vise grasps a given work blank by causing a movable jaw to be moved toward a stationary jaw fixed in position on one end of the vise bed. When the work blank is grasped between the stationary jaw and the movable jaw and the clamping force of the movable jaw is increased, no bending stress is exerted upon the vise bed and a force causing the movable jaw to be directed to the surface of the slide for the movable jaw is applied thereto to thereby increase the force of adhesion of the movabe jaw to the vise bed, with the result that the work blank is prevented from rising off the vise bed, that the rigidity and structural strength of the vise as a whole are increased and that the jaws grasp the work blank therebetween in a state wherein the jaw plates of the jaws keep their postural angle relative to the surface of the slide for the movable jaw at a precise right angle at all times.