CBSE-2017 Syllabus for Engineering Graphics Classes XII
Theory of Class XII 3 Hours and 70 Marks
Isometric projections of solids, Machine Drawing, Drawing of Machine parts
Assembly Drawings and Dis-assembly drawings
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Unit I: Isometric projection of solids 50 Pds
- Construction of isometric scale showing main divisions of 10mm and smaller divisions of 1mm, also showing the leading angles. Drawing helping view/s such as triangles, pentagon, hexagon etc using isometric scale.
- Isometric projections (drawn to isometric scale) of solids such as cube, regular prism and pyramids (triangular, square, pentagonal and hexagonal), cone, cylinder, sphere, hemi-sphere, frustum of right regular pyramids (triangular, square, pentagonal, hexagonal) and cone, when they are cut by a plane parallel to the base. The axis and the base side of the solid should be either perpendicular to H. P./VP or parallel to HP and VP (Indicate the direction of viewing). Combination of two solids (except “frustum” of Pyramids and Cone) Keeping the base side parallel or perpendicular to H. P./V. P. And placed centrally together, axis of both the solids should not be given parallel to H. P.
- Question on frustum will be asked in vertical position only.
- Hidden lines are not required in isometric projection.
Unit II: Machine Drawing (as per SP 46: 2003)
Drawing of machine parts 36 Pds.
- Drawing to full size scale with instruments. 9 marks (Internal choice will be given between any two of the following). Introduction of threads: Standard profiles of screw threads square, knuckle, B. S. W. Metric (external and internal). Bolts (square, Hexagonal, Tee and Hook); Nuts: (square and hexagonal), Plain washer, combination of nut and bolt with or without washer for assembling two parts together, Single riveted lap joint with standard dimensions.
- Free-hand sketches-6 marks
Internal choice will be given between any two of the following:
Conventional representation of external and internal threads; studs (plain, square-neck and collar), screws (round-head, cheese-head, 900 flat countersunk-head, hexagonal socket-head and grub-screw). Types of rivets: snap head, pan head-without tapered neck, flat head and 600 countersunk flat head: Types of sunk-keys (rectangular taper, woodruff and double-head feather key with gib head on both ends).
Assembly drawings and Dis-Assembly drawings-82 Pds.
Internal choice will be given between: Assembly drawing and a Dis-Assembly drawing.
- In all Assembly drawings, half sectional front view will be asked. Side/End view or Top View/Plan will be drawn without section.
- In all the Dis-assembly drawings (asterix * marked only), only two orthographic views (one of the two views may be half in section or full in section) of any two parts.
- In all sectional views, hidden lines/edges are not to be shown.
- In all full views, hidden/edges are to be shown.
- Footstep-Bearing (only sectional front-view will be asked)
- Simple Plummer-Block (only sectional front view will be asked with only round brasses).
- Cotter-joints for circular-rods (socket and spigot joint)
- Cotter-joints for round-rods (sleeve and cotter joint)
- Cotter-joints for square rods (Gib and cotter-joint)
- Knuckle-joints (only sectional front view will be asked)
Tie-rod and Pipe-joint
- Flange pipe joint
- Unprotected Flange Coupling (having socket and spigot arrangement)
- Protected Flange Coupling
- Solid cast Iron Pulley (upto 200 mm diameter) having solid web
- Single groove V-belt pulley (upto 200 mm diameter)
Practicals pf 3 Hours and 30 Marks and 72 pds
To perform the following jobs from the given views of the prescribed Machine Block (One)
- Copy the given views-1 Marks
- Drawing the missing view with hidden lines-2 Marks
- Sketching the Isometric view vithout hidden edges-5 Marks
- To make the machine block of the above in three dimensions (not to scale but approximately proportionately). drawn with any medium i.e.. Thermocol, soap-cake, plasticine, clay, wax, orchsis (available with flowerists) etc. 7
“Computer aided design” CAD-Project-10
Project file to be submitted on the simple solids (Prism, Pyramids and frustums of equilateral triangle, square, pentagon and hexgon) or machine blocks as prescribed in part-I by using the “computer aided design” CAD software.
- Sessional work relating to machine blocks as prescribed. 3 Marks
- Viva-voice based on part-I and part-II-2 Marks
Total Marks is 30
- Engineering Graphics-Class XI-Pubished by C. B. S. E, New Delhi.
- Engineering Graphics-Class XII-Published by C. B. S. E. New Delhi.