1. ENGN103 Engineering Drawing lettering, lines and scale
Lecture 1

2. Structure of Presentation
Introduction
Tools for Drawing
Paper sizes
Title Block
Dimensioning
Lettering
Lines

3. Drawing
Artistic Drawing Technical Drawing

4. Why Engineering Drawing?
A drawing is a graphic representation of an object, or a part of it, and is the result of creative thought by an engineer or technician.
Engineering Drawing is a formal and precise way of communicating information about the shape, size, features and precision of physical objects.
Drawing is the universal language of engineering.
Introduction: Overview
Engineering drawing ENGN103

5. Drawing Tools To prepare a drawing, one can use:
Manual drafting instruments
Computer-aided drafting or design, or CAD.
The basic drawing standards and conventions are the same regardless of what design tool you use to make the drawings.
In learning drafting, we will approach it from the perspective of manual drafting.
If the drawing is made without either instruments or CAD, it is called a freehand sketch.
Introduction: Apparatus
Engineering drawing ENGN103

6. Manual drafting Table/Board
The basic mechanics of drafting is to place a piece of paper (or other material) on a smooth surface with right-angle corners and straight sides - typically a drafting table. A sliding straightedge known as a t-square is then placed on one of the sides, allowing it to be slid across the side of the table, and over the surface of the paper …
Parallel lines can be drawn simply by moving the t-square and running a pencil or technical pen along the t-square's edge, but more typically the t-square is used as a tool to hold other devices such as set squares or triangles. In this case the draftsman places one or more triangles of known angles on the t-square - which is itself at right angles to the edge of the table - and can then draw lines at any chosen angle to others on the page. Modern drafting tables come equipped with a parallel rule that is supported on both sides of the table to slide over a large piece of paper. Because it is secured on both sides, lines drawn along the edge are guaranteed to be parallel.
Introduction: Apparatus
Engineering drawing ENGN103

7. T-scale
Introduction: Apparatus
Engineering drawing ENGN103

8. Triangle / Set-square Set-square: 30 & 60, 45 Adjustable Triangle
Introduction: Apparatus
Engineering drawing ENGN103

9. protractor
Compass
Introduction: Apparatus
Engineering drawing ENGN103

10. Circle master Flexi-curve French curve Introduction: Apparatus
Engineering drawing ENGN103

12. Introduction: Pencils
Engineering drawing ENGN103

13. Introduction: Paper Size
Engineering drawing ENGN103

14. Paper sizes
Introduction: Paper Size
Engineering drawing ENGN103

15. Introduction: Title Block
Engineering drawing ENGN103

17. Introduction: Lettering
Engineering drawing ENGN103

18. Thick- HB grade pencil Medium- H Grade pencil Thin- 4H grade pencil
Introduction: Lines-Home Work
Engineering drawing ENGN103

20. Drawing scale
The ratio of the length in a drawing (or model) to the length of the real thing. 1: 10, 1:1, 1:200 etc Example: in the drawing anything with the size of "1" would have a size of "10" in the real world, so a measurement of 150mm on the drawing would be 1500mm on the real horse.
A drawing that shows a real object with accurate sizes except they have all been reduced or enlarged by a certain amount (called the scale)is a scale drawing.

21. SCALE
When the object is bigger than the size of drawing sheet, it is drawn at reduced scale.
Therefore, scale is the ration of actual object and the size shown on the drawing. The scales are designated as:
SCALE 1: X for reduced scale (X is the ratio)
SCALE X:1 for enlarged scale
SCALE 1: for full size
Standard recommended ratios are multiples of 2, 5 and 10 as:
Enlargement: 50:1, 20:1, 10:1, 5:1, 2:1
Reduction: 1:2, 1:10, 1:20, 1:50, 1:100, 1:200, 1:500, 1:1000, 1:2000, 1:5000