 Hello friends, myself, Professor Narendra Kartikar, Assistant Professor, Department of Mechanical Engineering, Valachandha Institute of Technology, Solapur. We are going to see the topic of machine drawing, DIS conventions. The learning outcome for this particular topic at the end of this session, student will able to understood the need of BIS conventions. Student will be able to apply these BIS conventions to the part drawing. The content for particular topic BIS conventions, it will flow like this, introduction, we will see the need of BIS conventions, BIS conventions for geometries. In the introduction, let us see the few of the things related to machine drawing and various conventions for the same. Machine drawing is one of the extension subject of engineering graphics. The graphics, rather the drawing is an engineers language, whatsoever an engineer is going to create, define and explain that could be done with the help of particularly the representation that is drawing. Now particular various conventions are there, required to show various geometries for the machine elements, machine elements part geometry and many more things. The machine drawing creates, builds various kinds of drawings for communication. These drawings are required to be covered all the details in a representation manner. Let us go with the need of BIS conventions. Now as we had seen earlier, you might be knowing the various type of drawings, that is production drawing, assembly drawing, other drawings, applications also with the help of drawing methodologies, like maintenance drawing, like particularly the drawings used for identification of defaults etcetera. Remember we are talking about the production drawing, it is a drawing used for manufacturing the respective geometry rather the part in the organization with the help of distinct methods of the manufacturing, where the particular drawing need to be easily readable, without much more complexity, easily understood the relevance of the dimensions and geometries and many more. Likewise for assembly drawing, the part drawings consist the number of elemental drawings with the varieties of geometries. Now when such kind of geometries are presented on a single large sheet, it will be visualized in a very complex manner. For easy understanding of various geometries, many a times it does not require to be represent as actual. Instead of actual geometries to be shown for part, we are going to use the respective convention for the same. Bureau of Indian Standard is an organization set by the government for the uniformity of all the particular geometry conventions throughout the globe. As far as India is concerned, the respective geometries conventions are used somewhat similar as that of the convention used worldwide. This BIS convention strategy will nullify the complications, misunderstanding of all the engineers users for the particular communication drawings. Now let us go with one by one the BIS conventions. This is first group of conventions where the respective materials are to be shown with the distinct kind of cross sectional geometries. I will share one of your experience rather I will remind you, I will try to recall you your past experience of material convention usage. At the time of school days or in the college days for chemistry practical drawings purpose, you might have used the dash dash or dot dot kind of a geometry pattern for the visibility or showing purpose of liquids. This is nothing but indirectly we are used the particular BIS conventions over there. Now likewise the various type of materials are mentioned here and the patterns mentioned over here are going to be used to represent the respective material. One more example I would like to share that is about the glass, whenever you are going to draw the front view of the glass window, just rectangular frame body will not represent that it is a window. For the same the blank portion can be shown with such pattern so that the particularly physical element present over there will consider as the glass. Now these are the few materials where you can see the distinct patterns are there. At this stage of this session I will like to ask you, are you able to recall share some of the conventions for material representation which you had used earlier in the drawing or the sketches of any academic subject just enlisted. Yes, I think you can recall back for the particular application of concrete wood at the time of basic civil engineering and many more. Let us go with the further particular BIS conventions. Now many a times the fasteners that is screw, nut, bolts etc. are carrying out or having the fasteners are having the threaded geometry from the internal side or to the internal external side. The fasteners having the threaded geometry on the peripheral side may be outside or inner side. Now every time to show and represent the threaded geometry in the actual drawing it is bit difficult. Instead of that the two parallel lines can be used to represent the threaded geometry. This can be seen in this particular first two diagrams. Now for the slotted head whenever the slotted head fastener side view is going to be drawn it has to be shown 45 degrees at the particular ground level. Now whenever square end and flat ends are there whenever we are going to show the respective geometry we are going to use the cross mark for the same so that it will represent it will understood this is the flat portion. For radial ribs the significance of this particular convention is nothing but instead of showing the actual complicated structure of ribs it will be equally distributed and shown likewise. These three geometries are almost the same or similar serrated shaft spline shaft chain wheel where the convention is developed through the means of the logic. What is the logic? The logic is that the pattern is repeated for 360 degree now the here in the convention pattern is repeated for just small segment just for small particular degrees itself. So this whatever the serrated geometry spline shaft teeth geometry chain wheel teeth geometry is need not to be repeat for 360 degrees only small portion is quite sufficient. For ratchet and pinion you can see the same logic the particularly teeth shown over here is just a single for bearings all the type of roller bearing ball bearing etc the details of bearings are not necessarily be to be reproduced over there the convention used is cross mark. For gripping purpose many a times the knurling pattern is provided over there for example water bottle cap this whatever the water bottle cap carries the knurling pattern actually the knurling pattern is shown for the very small portion it may be a straight knurling or diamond knurling the particularly holes on linear pitch or circular pitch once again the pattern shows that very few of the holes are shown and rest of the positions are shown with the center lines representing the axis of the holes. This is the last repeated part where the outer geometry of the repeated part is going to be only proceed further after producing a first geometry. So here three number of repeated part one repeated part full geometry will be shown and rest of the geometry only shown with the outer geometry. Now we are coming to the end session of this particular topic that is BIS convention the references for this machine drawing by Siddheshwar Kananya Shastri Macangro Hill publication machine drawing by P.S. Gill S.K. Katarya and Sons publications thank you.