I B.TECH- I SEMESTER DEPARTMENT OF MECHANICAL ENGINEERING ENGINEERING DRAWING

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1 I B.TECH- I SEMESTER DEPARTMENT OF MECHANICAL ENGINEERING ENGINEERING DRAWING

2 ENGINEERING DRAWING UNIT-V DEFINITIONS: Axonometric Trimetric Dimetric Isometric It is a parallel technique used to create a pictorial drawing of an object by rotating the object along one or more of its axes relative to the plane of In this the direction of viewing is such that all of the three axes of space appear unequally foreshortened In this the direction of viewing is such that two of the three axes of space appear equally shortened, of which the attendant scale and angles of presentation are determined according to the angle of viewing In this the most commonly used form of axonometric in engineering drawing. Here all three angles are equal. The isometric is the least pleasing to the eye but is the easiest to draw and dimension. Drawing the Three-dimensional object using its isometric lengths with the help of isometric scale Isometric view Multiview Isometric axis Isometric lines Non Isometric lines Isometric scale Projection Plane of Projectors Parallel Orthographic Representing the Three-dimensional object using its true lengths In this only two dimensions of an object are visible in each view and hence more than one view is required to define the object Axis which are equally inclined and to the plane of and perpendicular to each other Lines which are parallel to the Isometric axis are called Isometric lines Lines which are Isometric lines not parallel to the Isometric axis are called It is the scale which is used to draw isomteric using isometric lengths (reduced lengths (0.82* true lengths) Representing the shape and size of an object in the form of figure in a plane A plane on which the is to be drawn Lines that has been drawn from each and every corner of the object Projection in which all the projectors are parallel to each other Projection in which all the projectors are parallel to each other and perpendicular to the plane of

3 CONCEPTS: I. First Angle of Projection 1. The object lies between the observer and the plane of. 2. The object is above HP & in front of VP. 3. The front view of the object is above XY & top view is below XY. II. Third Angle of Projection: 1. The plane of lies between the observer and the object. 2. The object is below HP & behind of VP. 3. The front view of the object is below XY & top view is above XY. III. Projection Symbol: It is mandatory that the system of used, namely first angle/third angle, should be symbolically specified in the title block. These symbols are the two views of a frustum of a cone whose axis is horizontal.

4 IV. Isometric Axonometric Projections: An isometric is a true representation of the isometric view of an object. An isometric view of an object is created by rotating the object 45 about a vertical axis, then tilting the object (see figure 3, in this case, a cube) forward until the body diagonal (AB) appears as a point in the front view. The angle the cube is tilted forward is The 3 axes that meet at A, B form equal angles of 120 and are called the isometric axes. Each edge of the cube is parallel to one of the isometric axes. Line parallel to one of the legs of the isometric axis is an isometric line. Planes of the cube faces & all planes parallel to them are isometric planes.

5 IMPORTANT QUESTIONS: 1)Draw the front view, top view and left side views of the Gib-Head key. Shown in Figure (ALL dimensions are in mm). 2)Draw the elevation, plan and left and right side views of the bracket shown in figure (ALL dimensions are in mm).

6 3)Draw the elevation, plan and right side view of the part shown in figure (ALL dimensions are in mm). 4)Draw the front view, top view and left and right side views of the object shown in figure (All dimensions are in mm). 5) Draw the isometric of a pentagon of side 30 in Horizontal position. 6) Draw the isometric view of a cylinder of base diameter 40 and height 100 in Horizontal position