is a connection that allows the connected object, such as a gun
to rotate horizontally and/or vertically. A common design for a swivel is a cylindrical rod
that can turn freely within a support structure. The rod is usually prevented from slipping out by a nut
or thickening of the rod. The device can be attached to the ends of the rod or the center. Another common design is a sphere
that is able to rotate within a support structure. The device is attached to the sphere. A third design is a hollow cylindrical rod that has a rod that is slightly smaller than its inside diameter inside of it. They are prevented from coming apart by flanges. The device may be attached to either end.
A swivel joint for a pipe is often a threaded connection in between which at least one of the pipes is curved, often at an angle of 45 or 90 degrees. The connection is tightened enough to be water- or air-tight and then tightened further so that it is in the correct position.