1. Unit 16 Engineering Drawing

2. Engineering Drawing Aims:- Introduce Oblique Projection .
Identify dimensioning techniques
Objectives:-
Identify the cavalier and cabinet oblique drawing projection.
Recognise the BS standard dimensioning.

3. The Orthographic Projection 1st angle is viewed as shown below, plan, side and front projection

4. First Angle projection: The object placed in the first quadrant Third Angle projection: The object placed in the third quadrant

5. Oblique Projection
Oblique projection is a method of drawing objects in 3 dimensions. It is quite a simple technique compared to isometric or even perspective drawing.

6. Cavalier Oblique & Cabinet oblique
In this convention the angles used are 45 degrees and 90 degrees.  The only difference between the two named styles is in the scale of the dimension going away from the viewer.

7. Dimensioning
The purpose of dimensioning is to provide a clear and complete description of an object.
Accuracy: correct values must be given.
Clearness: dimensions must be placed in appropriate positions.
Completeness: nothing must be left out, and nothing duplicated.

8. Dimensioning
A dimensioned drawing should provide all the information necessary for a finished product or part to be manufactured. An example dimension is shown.

9. Linier Dimensioning
It is very important to add dimensions (measurements) when drawing accurate.  

10. Diameter & Radius Dimensioning
This type of dimension is normally used for a circle.
Curved corners can be dimensioned like this. 'R' means.

11. Dimensioning Example of a standard dimension.
If a measurement is 9mm or smaller the
dimension is drawn in a slightly different way.

12. Angular Dimensioning

13. Dimensioning Diameters

14. Lettering
All notes and dimensions should be clear and easy to read. In general all notes should be written in capital letters to aid legibility. All lettering should be of the same size and preferably no smaller than 3mm. An example typeface is shown below.

15. Arrowheads Arrowheads are used as terminators on dimension lines. 1st
200
R 8.5
1st
2nd
3rd
4th