An adjustable spanner, shifting, shifting spanner, adjustable-angle head wrench, or crescent wrench is a tool that can be used in loosening or tightening a bolt or nut. It comprises of a jaw, the part where the bolt or nut goes, which is adjustable in size. This jaw permits various sizes of bolts and nuts to be handled with the same adjustable spanner.
The adjustable spanner is allegedly invented by Edwin Beard Budding when he used a screw to replace a wedge which fixed a jaw of a famous type of adjustable spanner. Another is Johan Petter Johansson who used a screw to fix and adjust the jaw. Monkey wrenches are another name for adjustable spanners long ago.
Types of adjustable spanners
There are many kinds of adjustable spanners, one is the taper lock spanner which needs a hammer to set a moveable jaw to a size of a nut, and another is the modern screw spanner. Other forms of adjustable spanners can automatically be adjusted to a size of a nut. The most modern of which are the digital types which make use of feelers or sheets in setting the size and other simple models that utilize a serrated edge in locking moveable jaw to its size.
Using adjustable spanners
In using adjustable spanners, the movable jaw should be tightly attuned to the bolt or nut so that it would prevent rounding. Also, it is very important to make sure that the movable jaw is placed on the side towards the rotation being performed. This decreases the risk of deforming the adjusting mechanism or the movable jaw of the adjustable spanner.