 Hello everyone, this is Shila Ratna Banshwade from Walshchan Institute of Technology, Solabor. As a part of machine drawing curriculum, we are going to see the basics of machine drawing. What are the basics, what conventions do we need to follow, what rules do we need to follow, we will be dealing with in this video. Let us move further, learning outcomes. At the end of this session, students will be able to classify the drawings. What kind of different drawings are available as far as engineering is concerned. Also students will be able to correctly dimension the given drawings. So, two conditions that what are the types of drawings and how to dimension these types of drawings, we will see into detail. Moving further, as we all know, drawing is a language that engineers used to convey their idea or to convey any diagram to a third person. So, it is a graphical language, language of engineers. Drawing displays the exact picture of an object. As we all know, if you want to convey the thing in a short manner, we go for drawings or signs. The symbols that you see on roads, the symbols that you see on automobiles like lights symbol, horn symbol, these are all drawings that convey the exact picture of the object. They convey the exact idea without the use of words and they convey very easily. And as we all know, there are no barriers to use these kind of symbols, these kind of drawings throughout the world. A horn symbol and a slash over it clearly indicates that there should not be blowing a horn in this area or a symbol of a mobile, a diagram of a mobile and a slash over it indicates that use of mobiles is prohibited. So, around the world, across the world diagrams can be used, drawings can be used to convey the ideas. You can say that it is a universal language of all engineers. Not only engineers, but drawing conveys the ideas very easily. As far as engineering drawing is concerned, it is a universal language. As we have certain standards, we have certain rules, we have certain principles on the basis of which we go on drawings, we will move further. Now what is the need for correct drawing? The drawing is a thing prepared by technical persons and it needs to be very clear, there should not be any mistakes into it and there should not be more than one idea being conveyed. It should convey the exact idea without any mistakes and clearly. Also drawing forms an official document and thus the success or failure of that particular product or that particular idea depends on how clearly the idea is being put forth through the drawing. A slight minor mistake in the drawing can lead to a bigger manufacturing defect if the drawing is provided to any production unit. So, clear, correct and accurate drawings have made the possibilities to manufacture big machines and automobiles that too on a mass scale. Correct and precise drawing conveys the correct idea that helps in the manufacturing of accurate product with accurate dimensions. Thus it is very much important to understand, to get know the principles and conventions of drawings that are being used or that are being needed. Let us see further how drawings are classified. The first and the very most type of drawing is the machine drawing. This is the machine drawing, this indicates a component of a machine element. This is a simple machine element drawing and here is a component being represented by the drawing. This gives you sectional area where sectional cutting plane and this is the sectional view all dimensions and nodes are being provided over it. Any drawing of a machine component is called as machine drawing. Next we have production drawing. In production drawing you can see there are certain additional elements being added like here geometrical tolerance is added, surface roughness what kind of surface roughness is required is added, there are certain tolerance is being added. So, this drawing is given for production unit with all manufacturing details. Here you can see the machining symbol, what kind of machining to what allowance it needs to be machined, every manufacturing detail is being mentioned on this. So, this is called as production drawing. Then we have assembly drawing. Assembly drawing is a drawing of all the assembled components, a single unit, all the components that are being assembled and then the drawing is drawn. For assembly drawing you provide a table, a table is provided over here. Then we have catalogue drawing, catalogue drawing is provided with the product. When you buy a product there the catalogue drawing is provided. Then we have assembly drawing for instruction manuals. When you buy a new automobile you have a manual and in that you can find these kind of drawings where each parts are being numbered and the description of each part is given in this side. So, this is assembly drawing for instruction manuals. Then we have exploded drawing. Exploded drawings are also provided with the products where you need to assemble the products. So, how each part fits into it or how each parts can be removed is shown in this exploded view and each part is being numbered and the name for each part is given in side. Then we have schematic assembly lines or schematic assembly diagrams. Schematic assembly diagrams are used where very detailed drawing is not possible and you want to convey how power is being transmitted or how the flow of energy is going to take place to the drawing. As you can see here it is a prime ore and this is how the power is being transmitted with the help of gears. So, this is a line diagram, a simple line diagram is called a schematic assembly diagram. Then coming to dimensions. As we all know dimensions are the number values that expressed that are expressed with the help of appropriate units. In the previous drawing also you can see there are certain dimensions being provided. So, these are dimensions. See it is indicated on drawing using lines or symbols and nodes. Going back see these are represented with the help of symbols, these are represented with the help of nodes and number values. Depending upon what you want to convey the dimensions can be used. They completely define the feature. What kind of size, what kind of shape, what kind of machining is required is conveyed with the help of dimensions. Then elements of dimensions. Now this is the origin of dimension where you start the dimension for this particular product or this particular component. This is where you start the dimensions. Then you go on continuing. So, this is called as the origin, this is called as the origin. Then the dimension is terminated with the help of arrow head. Here is the termination of the dimensions. This is called as leader line, this is called as leader line where you mention a note over it. Now, these are projection lines that you project from the object. These are projection lines, lines of projections. Then this is the value of dimension. This is the value of dimension. So, these are some of the elements. Some of the elements this is called as the dimension line that are used during dimensions. Now, coming to types of dimensions, here you see on screen are aligned dimensions. As the shape or inclination of the boundary of object goes on, you incline the dimension value also. See here it is inclined, here it is straight, so it is straight, here it is exactly vertical, so exactly vertical. Now, here in different angles you can see the value 20 is been inclined in different directions. Here also in different directions, the value 60 is inclined. So, these are called as aligned dimension. They align themselves to the boundary of the objects. Then we have unidirectional dimensions. No doubt or without any consideration of the inclination of the boundary of the object, the dimensions are given exactly vertical as you can see on screen. So, irrespective of the inclination of the boundary of the object, here exactly 60, exactly vertical the value 60 is mentioned. Then we have arrangement of dimensions, how the dimensions are arranged or how the dimensions can be arranged on a diagram or on a drawing. Here you can see the dimensions are in line one after the other, one after the other, here also one after the other. So, they form a chain like pattern and hence called as chain dimensions. Chain like pattern hence called as chain dimensions. Then we have parallel dimensions next to each other, next to each one below the other, one above the other, exactly here. We have a single point of origin over here. From this reference the dimensions are measured. In a drawing you can use a combination of both, chain dimension as well as parallel dimensions. Then we have dimensioning methods for diameters. As you can see on screen, these are some of the dimensioning methods that you can use for diameters or dimensioning diameters. Here you can use a symbol phi, phi here, see for an arc you use radius. For a complete circle you go for symbol phi with the value of diameter. So, phi represents diameter, phi represents diameter, r represents the radius. Then dimensioning of thread and tapers as you can see on screen. Here taper on both the side, so triangle is used. Here trapper on one side, so only this triangle, right angle triangle is used. Here you both side you have a triangle, single taper. Here it is thread both side taper. Then these are certain points to be remembered which indicates that dimension should not be given on the drawing. They should be represent on left and right or right hand side of the drawing. Two dimensions should not cross each other, they should be separately aligned. Now I suggest you to kindly go through pause the video and go through these points. So all what are the principles, what are the basic rules that we follow during dimension are mentioned over here on the screen. As far as possible dimension should not be given on the drawing. It should be side of the drawing. It should be on the side of the drawings. These are the references. Thank you.