Engineering Drawing (2nd)

 Sheet 1. Lettering

12Feb13

Sheet 2. Scales Plain Diagonal Vernier & Comparative Scale

·        What is scale?

Scale is used to reduce or to average the view of an object.

Drawing Scale-

1:1- Full size

1:2- Half Size

Drawing Scale indicate the given drawing is reduced, enlarged or full size.

Plain Scale- It represents either two units or one unit and its fraction. It consists of a line divided into suitable number of equal parts where first part (unit) sub-divided by required no.

Diagonal Scale- It represents either three unit or one unit & its second place of decimal point. It consists of a line divided into suitable number of equal parts where sub-divided first pat is further sub-divided by dagonals.

Vernier or Vernier Scale- It is an auxialry scale its slides across the main used to read a main scale division with a great accuracy.

Least Count- is the smallest measurement that can be measured by that instrument.

L.C. of a watch is 1sec

Comparative Scale- having same representative fraction, but graduated to read different unit.

It can be constructed one above the other or separately. It may be plain scale or diagonal scale.

Representative Fraction=Drawing dimension/Actual dimension

1. Construct a Plain scale to show metres when 1cm represent 4meters and can measure upto 60metre. Find R.F. and show a distance of 47metres on you scale.

2. Draw a diagonal scale where 3cm represents 1metre showing metre. Decimetre & centimetre 7 can measure upto 5 metre. Find the R.F. and show the length of a) 2.33 m b) 4.67m on your scale.

3. Construct a vernire scale of RF- 1:25, to show metre, decimetre & centimetre. The scale should be capable of reading 4metre. Mark the following distances a) 2.43m b) 3.67m on the scale.

4. Construct a comparative scale to measure a) 45miles b)70 km to be used with a roads map. On this map a distance of 15miles is shown by a 5cm line. Show the distance (1mile=1.609km) of a) 37miles & b) 55 km on the scale.

5. The distance b/w 2 station A & B is 100km& equivalent distance on railway map measures 2.5cm. What is the R.F.? Draw a diagonal scale showing single km & indicates on scale the following distances.

i) 577km ii) 455km iii) 333km

02March13

Sheet 3. Geometrical Constructions & Curves

1. Draw a regular hexagon & pentagon of sides 3cm perpendicular to vertical plane & parallel to horizontal plane.

2. A cricket ball thrown from a ground level, reaches the wicket keeper’s gloves. Maximum height reached by the ball is 5m. The ball travels a horizontal distance of 11m from the point of projection. Tarce the path of the ball (Take a suitable)

3. Construct an ellipse by concentric circle method whose major & minor axes are 90mm & 60mm respectively.

23March13

4. A plot of ground is in shape of a rectangle 110mX50m. Inscribe an elliptical lawn in it. Take a suitable scale.

5. Construct an ellipse by one half concentric circle method and other half by oblong method whose major & minor axes are 100mm & 60mm respectively.

6. Construct an ellipse by four centres method whose major &; minor axes are 100mm & 60mm respectively.

7. Construct a rectangle hyperbola when a point P on it at a distance of 20mm and 25mm from two asymtotes.

Sheet 4. Projection of Points Lines & Surfaces

First Angle Projection- The object is assumed to be placed on first quadrant, i.e. the object is in between the observer and the plane of projection. Front/ Elevation will be placed above the GL(Ground Line) & Top/Plan will be below the front/elevation.

Third Angle Projection- The object is assumed to be placed on third quadrant, i.e. the plane of projection is in b/w the observer and the object. Front/ Elevation will be placed below the GL(Ground Line) & Top/Plan will be above the Front/Elevation.

·        Why don’t you follow the 2^nd Angle & 4^th angle projection?

For Plan/Top view, we have to rotate horizontal plane at 90 degree in clockwise direction. For that horizontal plane will coincide with the vertical plane on both the cases. Then it is very difficult to distinguish the views of an object.

Any kind of representation of an object on a paper screen on similar surface by drawing  or by photography is called projection.

1) Pictorial Projection

If the length, breath & height is shown in one vuew then that projection is called Pictorial Projection

2) Orthogonal Projection

In a projection when projectors are parallel to each other but perpendicular  to the plane of projection is called Orthogonal Projection

A- 30mm above HP & 40mm in front of VP

B- 50mm above HP & 60mm behind VP

C- 30mm below HP & 40mm behind VP

D- 20mm below HP & 30mm in front of VP

E- 30mm above HP & on VP

F- 20mm above VP & on HP

G- 20mm on VP & on HP

H- 30mm below HP * 30mm in front of VP

I- 30mm above HP & 30mm behind VP

               Figure  No. 1.............

1. A line AB-70mm long inclined at 30degree to HP, pt. A is 20mm above HP and 15mm in front of VP. Draw the projection line.

2. A line AB-80mm long inclined 45 degree to VP & parallel to HP. Draw the projection line pt. A 20mm above HP & on VP.

3. A line 75mm long inclined at 30degree to HP & 45degree to VP. pt. A is 20mm above HP & 15mm in front of VP. Draw the projection line.

4. A line AB 120mm long inclined at 45Degree to HP & 30degee to VP. Its mid-pt. C is 20mm above HP & 10mm in front of VP. Point A is in the 3^rd quadrant and B is in the fIrst quadrant. Draw the projection of the line.

5. A hexagonal plane of sides 30mm rests on one of its edge on HP such thaT its surface is inclined at 45degree to HP & the edge on which it rests inclined at 30degree to VP. Draw the projection of the plane.

6. A pentagonal plane of sides 30mm rests one of its edge such that the surface is inclined at 30degree to HP and the edge on which it rests is inclined at 45degree to VP. Draw the projection of the plane.

13April13

Sheet 5. Projection of Solid

1. Draw a regular hexagonal/pentagonal right prism/pyramid of sides 30mm.

2. A hexagonal prism of base side 30mm & 70mm long is resting on its HP with an edge of the base is perpendicular/parallel to VP. It is cut by a section plane perpendicular to VP inclined at 45degree to HP & bisects the axis. Draw three views of the solid and true shape of the section.

3. A pentagonal pyramid of base 30mm side & axis 70mm long has its base on HP and one edge of the base is perpendicular to VP. It is cut by a section plane perpendicular to VP and inclined at 45degree to HP & passing through the axis at 35mm above the base. Draw the sectional, front, top, side view & true shape of the solid.

4. A square prism with 40mm edges & axis 55mm long, rests on its base on HP with its side equally inclined to the VP. A concentric circular axial hole of 20mm diameter is cut through the prism. The prism cut by a cutting plane perpendicular to the VP & inclined at 60degree to the HP bisecting the axis. Draw front view, sectional side view & true shape of the solid.

27April13

Sheet 6. Section of Solid

Development

If it is imagined that the surface of a solid is enclosed by a thin paper like wrapper & then the wrapper is opened out & laid on a flat plane, then the flattened out paper is called the development of the surface of that solid.

Shape occupied by the solid is called development of the surface.

1. A hexagonal pyramid of side of base 30mm and length of axis 80mm is kept on the ground on the base. It is cut by and AIP (Auxiliary Inclined Plane) inclined at 60degree to the base and cutting the axis at 60degree to the base and cutting the axis at 40mm from apex. Draw the development of lateral surface of the pyramid.