CBSE Class 12 Engineering Graphics Syllabus

COURSE STRUCTURE
CLASS XII (2023-24)
One Paper (Theory): 3 Hours                   70 Marks
One paper (Practical): 3 Hours                30 Marks

S. No.            Unit Name                                              Marks         Periods
I       Isometric Projections of Solids                                 25            60
II      Machine Drawing                                                     45            114
        A. Drawing of Machine parts
        B. Assembly Drawing and Dis-assembly drawings
        1. Bearings
        2. Rod joints
        3. Tie-rod and Pipe joint                                          
         Practical                                                                30               66
        Total Marks                                                           100             240

THEORY
Unit I: Isometric Projection of Solids 60 Periods

(i) Construction of isometric scale showing main divisions of 10mm and smaller divisions of 1 mm, also showing the leading angles. Drawing helping view/s such as triangles, pentagon, hexagon, etc., using isometric scale.
(ii) Isometric projection (drawn to isometric scale) of solids such as cube; regular prisms and pyramids (triangular, square, pentagonal, and hexagonal); cone; cylinder; sphere; hemisphere. The axis and the base side of the solid should be either perpendicular to HP / VP or parallel to HP and VP.
(iii) Combination of any two above mentioned solids keeping the base side parallel or perpendicular to HP/VP and placed centrally together (Axis of both the solids should not be given parallel to HP).

Note:
1. Hidden lines are not required in isometric projection.
2. Indicate the direction of viewing.

Unit II: Machine Drawing (as per SP46: 2003) 114 Periods

A. Drawing of machine parts
(i) Drawing to full size scale with instruments. 30 Periods
(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 head, hexagonal head; Nuts – Square head, Hexagonal head; Plain washer,Combination of nut and bolt with or without washer for assembling two parts together.
(ii) Free-hand sketches 10 Periods
Conventional representation of external and internal threads; Types of studs– Plain stud, Square-neck stud, Collar stud; Screws (round-head, cheesehead, 900 flat counter sunk head, hexagonal socket head and grub-screw);
Types of rivets – Snap head, Pan head (without tapered neck), Flat head, 600 countersunk flat head.

B. Assembly drawings and Dis-Assembly drawings
(Internal choice will be given between an Assembly drawing and a Dis-Assembly
drawing). 74 Periods
1. Bearings
(i) Open-Bearing
(ii) Bush- Bearing
2. Rod-Joints
(i) Cotter-joints for round-rods (Sleeve and cotter joint)
(ii) Cotter-joints for square rods (Gib and cotter-joint)
3. Tie-rod and Pipe-joint
(i) Turnbuckle
(ii) Flange pipe joint

Note:
1. In all Assembly drawings, half sectional front view will be asked.
Side/End view or Top View/Plan will be drawn without section.
2. In all Dis-assembly drawings, only two orthographic views (one of the two views may be half in section or full in section) will be asked of any two parts only.
3. (a) In all sectional views, hidden lines/ edges are not to be shown.
(b) In all full views, hidden lines/edges are to be shown.

PRACTICALS 66 Periods
(i) To perform the following tasks (for One only) from the given views of the prescribed fifteen (15) machine blocks in ANNEXURE-I.

Value-Points

1. Copy the given views                                                                                 1
2. Drawing the missing view with hidden lines                                               2
3. Sketching the Isometric view without hidden edges                                  5
4. To make the machine block of the above in three dimensions.
(Not to scale but approximately proportionately drawn with
Any medium i.e., Soap-cake, plasticine, clay, wax, floral foam brick
(available with florists), etc.                                                                             7
(ii) Computer Aided Design (CAD) – Project                                                 10
Project file to be submitted on the simple solids or machine blocks as
prescribed in part-I by using the CollabCAD software or any equivalent
pertinent software.
(iii) (a) Sessional work relating to machine blocks as prescribed.                  3
(b) Viva-voce based on part-I and part-II 2
Total Marks                                                                                                   30

ACTIVITY
Industrial Visits (Two) to any industry/ manufacturing plant to acquaint the students with the present - day methods & technology for better conceptual understanding.