We saw various types of jaw spanners previously but certain situations require the bolts and nuts to be placed in such a position that makes it very difficult, if not impossible, to open them by using jaw spanners. The types of spanners used in such a situation are known as box spanners. They are made in such a manner that they grip the entire head of the nut or the bolt instead of just gripping two faces. This way it provides for a very strong grip which means that much more force can be applied to the handle without the danger of the spanner head slipping from the nut or the bolt to be opened.
Box spanners also come in several form and one such useful variant is a tubular type box spanner. As the name itself suggests, it consists of a steel tube which has hexagonal heads on both sides which fully cover the head of the nut or the bolt to be opened. The uniqueness of this variant lies in the fact that instead of a fixed handle at the end, it consists of holes on both sides of the tube which can be used to insert a steel rod of the corresponding diameter which helps to exert force without any loss arising out of misalignment of the spanner. The rod which is inserted is also known by the name of a Tommy bar.
Another type of spanner which is very similar in design to a box spanner is the socket spanner. It is similar in the sense that the socket head of the spanner covers the nut/bolt completely and the handle is not fixed to the head. However it is different in that it does not have a Tommy bar type arrangement, but the socket itself has a projection which is either square shaped or hexagonal shaped. This projection fits into the appropriately sized cavity on top of the key or the handle which can be used for the application of force. If you are not very clear about this description better see the picture relating to this type of spanner and everything will be crystal clear.
In the next series we will continue our study of the spanners and will later study various types of pliers, hammers and so forth. This is certainly going to be an interesting study, so just stay tuned.