A garter spring is a coiled metal spring whose ends can be fastened together to make a ring. It is used to reinforce a rubber seal around pipe joints or a rotating shaft. Since one of their most common uses is to secure seals around oil pipes, they are also known as oil springs.
A garter spring is typically fitted inside a rubber seal. With pipes carrying liquid, the garter spring ensures that the seal remains secure even if the pipe's size changes slightly due to the pressure and temperature of the liquids being carried through it. When used around a rotating shaft such as an axle, they help hold in lubricants for the shaft. Their expandability helps them maintain a tight seal even when under pressure.
Originally, oil seals were made of tanned leather, which was flexible enough to deal with the changing pressures of the oil pipes. Many companies that now manufacture seals used to be tanneries. Garter springs, along with rubber and man-made joint lubricants, came into use when automobiles and other machines developed that demanded tougher seals that could withstand higher speeds and temperatures.
Choosing the right size of garter spring involves taking into account many different factors. The material, the diameter of the joint and the amount of pressure the garter spring will be under can all be plugged into a mathematical equation to find the needed spring strength. Taking care with the calculations ensures that the ends of the garter spring will not come apart under stress.
Though some garter springs can be bought pre-cut, they are often sold simply as straight lengths of spring. These springs are sold as stock in various weights. When a garter spring is needed, a mechanic can simply snip off the length they need and screw the ends together.
Depending on the style, garter springs are secured in a variety of ways. The two ends of the spring can be threaded onto each other and screwed together. They can also be soldered together or secured with a separate screw.
Garter springs are removed using a special tool. A garter spring removal tool is a kind of tube which slips down over the pipe or joint under the garter spring. It expands the spring so that new seals can be slid under it without having to undo the spring. Once it's been expanded, the seals underneath can be replaced or removed, and the pipe or joint can be unscrewed.