# CBSE-2016 Syllabus for Engineering Graphics Classes XII

## Theory of Class XII 3 Hours and 70 Marks

 Unit Marks Isometric projections of solids, Machine Drawing, Drawing of Machine parts 15 Marks Assembly Drawings and Dis-assembly drawings 30 Marks Bearings Rod joints Tie-rod and pipe joints Couplings Pulleys 25 Marks Totals 70 Marks

### Unit I: Isometric projection of solids 50 Pds

1. 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.
2. 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.

Note:

1. Question on frustum will be asked in vertical position only.
2. Hidden lines are not required in isometric projection.

### Unit II: Machine Drawing (as per SP 46: 2003)

Drawing of machine parts 36 Pds.

1. 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.
2. Free-hand sketches-6 marks

Internal choice will be given between any two of the following:

Assembly drawings and Dis-Assembly drawings-82 Pds.

Internal choice will be given between: Assembly drawing and a Dis-Assembly drawing.

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 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.

### Bearings

1. Open-Bearing
2. Bushed-Bearing
3. Footstep-Bearing (only sectional front-view will be asked)
4. Simple Plummer-Block (only sectional front view will be asked with only round brasses).

### Rod-Joints

1. Cotter-joints for circular-rods (socket and spigot joint)
2. Cotter-joints for round-rods (sleeve and cotter joint)
3. Cotter-joints for square rods (Gib and cotter-joint)
4. Knuckle-joints (only sectional front view will be asked)

### Tie-rod and Pipe-joint

1. Turnbuckle
2. Flange pipe joint

### Couplings

1. Unprotected Flange Coupling (having socket and spigot arrangement)
2. Protected Flange Coupling

### Pulleys

1. Solid cast Iron Pulley (upto 200 mm diameter) having solid web
2. Single groove V-belt pulley (upto 200 mm diameter)

## Practicals pf 3 Hours and 30 Marks and 72 pds

### Value-Points

1. Copy the given views-1 Marks
2. Drawing the missing view with hidden lines-2 Marks
3. Sketching the Isometric view vithout hidden edges-5 Marks
4. 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