Bolts

Today, bolts are safe and indispensable connecting elements in industry and in model making, but also safety elements that are used in thousands of different shapes and sizes. In this article we would like to tell you more about the different bolt shapes and pin bolts, how they are constructed and what materials are used, such as plastic bolts, aluminium bolts or steel bolts, or even the very high quality stainless steel bolts, which can be used in two different alloys, V2A and V4A. The manufacturing industry in particular requires metal bolts in thousands of designs, which have to perform safety functions on machine parts and components every day and also require a high load-bearing capacity. Also in model making, as already briefly mentioned, metal bolts are installed in many different positions, so that components can be connected with a kind of bolt joint and can exercise an axial rotational function without allowing radial misalignment. Of course there are other types of bolts, but not all of them can be discussed here in this article. However, we would like to go into more detail in this article about all pins that have a locking function and a safety function. We speak here in the form of bolts that can lock or bolts that can be locked. Every bolt that is installed in such standard parts has a very special structure. This structure of the bolts is exactly matched to the inner workings of such a standard part, so that the function continues to be given without problems. Basically, the industry does not use pure bolts made of plastics. However, these could be made of polyamide or another plastic. The load-bearing capacity of today's plastics has increased by far, but it is not sufficient for such securing functions, for example a bolt that is to lock a component or secure two components against each other, because the shear forces in particular are extremely high in relation to the bolt cross-section. The consequence would be a bolt breakage. This would be very bad, because a maximum of safety is required especially on machine and machine parts and for this reason alone, the use of bolts made of plastics is not possible. All other materials are shortlisted because the strengths are constantly increasing in relation to the cross-section. So bolts can be used in the following order of strength. The aluminium bolt is already much more resilient, but is also only used for light locking activities on machines when weight is still an issue. Then comes the pure steel bolt. This is already very high loadable, because steel corresponds to the fixed sliding classes. If you want to use the highest grade of bolt materials and want to combine strength or shear strength with corrosion, you should use the stainless steel bolt. As already mentioned, this is available in two different material alloys, which can be selected according to requirements. On the one hand there is the stainless steel V2A and also the V4A. V2A is usually sufficient if the bolt is installed in an environment that can come into contact with normal water or moisture. The highest level is the V4A stainless steel. This alloy is also resistant to alkalis and all acids and this stud material can be used in the chemical industry without any problems.

Basically, a bolt that is installed in a grid element as a standard part must take over a certain function and different materials are also used in such a residual element. We would now like to tell you more about the bolt grid element and how the different materials can be used. The body of the housing, which is to enable the entire locking function with the stud element, can be made of one metal. These metals include aluminium and also steel or stainless steel as V2A or V2A. On such a grid element base body there is always a head that can shy away from the screwed component to enable the bolt to be released. These heads on the basic bodies are not really ballastable and so these heads can be made of various plastics or metal, such as steel, stainless steel or aluminium. The variations are almost unlimited. The bolt can move up and down in the bolt housing in a standard part. This means that it can move acially and, due to its construction, also move radially, which is not really important for such a pin retention element. As already mentioned, the basic body of the bolt is made of metal and can be produced as a cast or turned part. The production of a cast basic body always requires the production as a casting. With this type of production of a stud base body, it is necessary to design a base body which is then produced in a wax part. This wax part can then be immersed in a mud bath and then be firmly fired in a subsequent firing process with above-average heat exposure. During this process the mud layer becomes very hard because the water evaporates. In the same breath the wax evaporates and a solid shell remains. This shell is the measure of all things and can be filled with liquid metal such as steel or stainless steel in the subsequent process. When the metal casting has cooled down, the coring process is done by destroying the layer. Now the stud body can be reworked and set up with the appropriate holes and fits for the stud. The bolt itself is never a casting but always a turned part. These turned parts are always produced on appropriate CNC machines. A loader is always connected to the machine, which is in direct communication with the machine. Once the correct metal billet material is loaded into the loader and the machine is set up, the production of the billets can begin. The first piece of raw material is now drawn into the machine and clamped in the chuck. Now the contours of the stud are turned in so that the stud can be cut off after a certain working process and then falls into a collecting container. If enough bolts are collected, they can be collected for the assembly of a locking bolt. In the last section we would like to look at the head area of the bolt body and take a closer look at the production process. In this example we assume that we are using a plastic head part. These plastics are produced in a completely different process and are later mounted on the bolt body. In this case, a metal mould consisting of two halves has to be milled so that it can be clamped in an injection moulding machine for plastics and filled with plastic under high pressure. When the plastic has cooled down, the mould opens and the bolt head can be removed. In the last working step, the base body of the metal bolt can be mounted together with the head and then the bolt that is to snap into place can be integrated into the base body. The finished component would then be ready as a standard part with a bolt as a grid element and can be installed.