 Hello everyone, this is Shila Ratna Banswade from Walchand Institute of Technology, Solapur. Today we are going to see the topic freehand sketch and in that we will be particularly focusing on bolts and nuts. Learning Outcomes Students will be able to describe different types of bolts and nuts. At this moment of the video, I suggest you to pause the video and remember the applications and the different types that you might have come across of the bolts and nuts. Let us move further. What are bolts and nuts? Bolt and nut together form a fastening device. There are various devices which are used or methods which are used to join different materials different components. Out of that nut and bolt arrangement is the most widely used and of low cost. The other types of joining devices or methods are riveting screws and couplings etc. But out of that bolt and nut is the most widely used device. The smaller part out of the bolt and nut is called the nut and the larger part is called as the bolt. The bolt body can be divided into two parts. The longer part is called as the shank and the top surface or the head surface is called as head which has different shapes like a square, a hexagonal or a circular with certain clamping arrangement. Square threads on the shanks are mostly preferred for better locking or better fastening applications. For nut, hexagonal shape is the most preferred one. So this is how we can define or we can state what is bolt and nuts. Let us move further. Now coming to types of bolts. The first and the widely used type of bolt is the hexagonal bolt. As you can see on the screen it has a hexagonal shape or a hexagonal head we can say. So this is the head part, this is the shank part and on the shank part there are threads over at this right hand side of the shank. The convention for the thread is shown over here. This is the most widely used bolt in most of the applications. You can see the parametric dimensions with respect to the diameter of the shank. The threading is two times of D, the diameter of shank is D, the head height is 0.75 D. The convention for external threads is shown over here in the front view and the total hexagonal size is of 2D. So this is how your typical hexagonal bolt looks like. It has wide applications in automobiles in many household equipment. Let us move to the next. This is a square headed bolt. As you can see this is the shank and this is the head. Now the head is in a square form, you can see it over here and this has a square shoulder. This part is also in a square form. When this bolt is inserted in the required application, this goes and fits into a square hole provided over there as well as this also fits into a square hole. This square shape avoids the moving of the bolt by itself. So this gives an additional clamping or fastening help for the bolt. So this is the area where square shoulder is provided. This type of bolt also comes without this square shoulder, a total shank of circular form. You can see the dimensional relation with respect to D as shown on the screen. T-headed bolt has a square shoulder as we have seen in previous type of bolt. This type of bolts are mostly used for clamping purposes on machines like drill or lathe machines to clamp the object or the job to the machine. This gives better clamping applications. You can see the parametric dimensions over here. The next type is hook bolt. Then the two surfaces to be joined out of that if one component doesn't have a space to drill a hole in it then we go for hook bolt. As you can see it has a holding kind of shape at the top at the part of the head. So the lower part is inserted into one component while the other component is hold with the previous component with the help of this holding shape. Thus this is called as hook bolt and its parametric dimensions are mentioned over here. Next eye bolt. You must have seen these kind of bolts in your workshop where you carry out your regular practicals on electric motors and etc. This kind of bolt is used to lift heavy machine components. A hole is drilled above the center of gravity of the object. Consider electric motor and in that this eye bolt is fitted. So you can lift the object by holding the bolt at this point. So it has a circular form over here to hold the bolt. This holding in turn lifts the object to which it is clamped. So mostly this type of bolts are used for lifting any heavy object. Example I repeat electric motors or any machine components found in mechanical workshops. Now let us move to next. This is a stud bolt. Till now we have seen bolts which has threads on one part whereas a head like structure on another part. Now stud is a type of bolt where both the sides of the rod have threads. So one part engages the one component to be joined and the other part is occupied by the nut and this is how clamping is done. So both the parts of the metallic rod are threaded. So you can see the thread conventions on both the parts and this is the middle part where threading is not done. Let us move to the next. Now coming to types of nut. Till now we have seen the different types of bolts. Now let us see what are the different types of nuts. The first one is hexagonal nut. Hexagonal nut is most widely preferred kind of nut. The reason is that with the help of hexagonal nut in the one sixth rotation of the spanner the nut can be moved. It can be tightened or loosened. So this is the benefit of using hexagonal nut. Next we have flange nut. Flange nut is a kind of hexagonal nut with a flange like structure attached to it. This is a single entity and a flange is found at the bottom. This type of nut is used where the hole size is big and you want to use a bolt over there. So clamping can be easily done with the help of this kind of flange nut. So it depends upon what is the hole diameter where you want to use the bolt. Next we have cap nut. Cap nut is again a type of hexagonal nut where there is a cap like structure at the top or a dome like structure over here. So cap nut and dome nut are nothing but similar. And this type of nuts are used in connecting the steam pipes or locomotives. This also prevents the corrosion or leakage where these kind of nuts are used. Next we have capstone nut. Capstone nut is a cylindrical structure with holes drilled on its lateral surface. These holes are used to tighten or loose the nut with the help of a metallic rod. The metallic rod can be inserted into this and the nut can be rotated to tighten or to loose the same. Next we have slotted nut. Slotted nut is a form of ring like structure and there are serrations at the top surface as you can see on the screen. Regular spanners cannot be used to turn these kinds of nuts. These kind of nuts are used where the regular kind of spanners are very difficult to be operated. So special type of spanners are used to operate these kinds of nuts. Wing nut. Wing nut is used where frequent opening and closing of the particular component is done. These nuts can be operated with the help of fingers or it can be operated manually without the help of any spanner. So you can see there is a wing like structure with the help of which this can be rotated. These are the references. Thank you.