1. Sketching & Drawing Projects
Unit 18

2. Objectives
Describe the difference between a sketch and a drawing and explain the different type of drawings.
Describe the procedures used to make mechanical drawings.
Properly letter drawings and sketches
Draw and sketch different views of objects
Read and interpret plan drawing
Prepare a bill of materials from a sketch or plan drawing

3. Introduction Why?????? Represent the shapes and sizes of objects
Aids in developing functional ideas on paper.
Aids in construction and repairs according specifications
Reduces the amount time, money, and materials needed for a project.
Aids in without the use of expert assistance

4. Sketches & Drawings Sketches Simply Rough outline of an object
Can be made freehand or a straightedge
Not drawn to scale
Sketches of small, simple projects with proper dimensions can be sufficient

5. Sketches & Drawings Drawings Requires scaled drawing
Made with drawing instruments
Pencil and ink are used
Usually ink over pencil for plans kept for long periods.

6. Pictorial Drawing
Pictorial drawings shows all three dimensions at once

7. Symbols
Border line – a heavy, solid line drawn parallel to the edges of the drawing paper.
Object line – a solid heavy line, less than border lines, showing visible edges and form of an object.
Hidden line – a series of dashes that indicates or shows the hidden features of a part.
Dimension line – a solid line with arrowheads at the ends to indicate the length, width, or height of an object or part.

8. Symbols
Extension line – a solid line showing the exact area specified by a dimension.
Break line – a solid, zigsag line used to show the illustration stops but the object does not.
Center line – a long-short-long line used to indicate the center of a round object.
Leader line – a solid line with an arrow used with an explanatory note to point to a specific feature of an object.

9. How to Sketch a Horizontal Line
1st – mark off two points spaced a distance equal to the length of the line to be drawn. Points should be parallel to the top or bottom of the page. . .

10. How to Sketch a Horizontal Line
2nd –Move your pencil back and forth and connect these points with a construction line. 3rd –Start from left point and sketch an object line to the right point. This line is sketched over the construction line.

11. How to Sketch a Vertical Line
1st – mark off two points spaced a distance equal to the length of the line to be drawn. Points should be parallel to the left or right side of the page. 2nd –Move your pencil back and forth and connect these points with a construction line.

12. How to Sketch a Vertical Line
3rd –Start from left point and sketch an object line to the right point. This line is sketched over the construction line.

13. How to Sketch an Inclined Line
1st –Mark off two points at the desired angle. Connect these points with a construction line. 2nd—Sketch the desired weight line over the construction line. Sketch up when the lines inclines to the right. Sketch down when the line inclines to the left.

14. How to Sketch Squares & Rectangle
See handout.

15. How to Sketch Angles
See handouts.

16. How to Sketch Circles
See Handout.

17. How to Sketch an Arc
See handout

18. How to Sketch an Ellipse
See handout

19. How to Sketch a Hexagon
See handout

20. How to Sketch an Octagon
See Handout.

21. Scale Drawing
Scale is the size of a plan or drawing as compared to that of the object it represent.

22. Types of Drawings
Orthographic drawings
Pictorial drawings

23. Orthographic Drawings
Shows separate views of an object
Top
Front
End or side
These views are referred to as working drawings

24. Pictorial Drawings Two basic types – isometric & oblique
Shows three views of the object together which resembles a picture of the object to be made

25. Orthographic Views

26. Pictorial View .

27. Mechanical Drawing Equipment
Drawing Board
20” X 26” softwood, free of knots
Accommodate 17” x 22” paper
Left and right edges of the board must be straight

28. Triangles
45 degree triangles
degree triangles

29. Isometric Drawing
Three views to transfer to an object top front side

31. THE BOX
top front side