1. 2D Drawing Representation
Chapter 5

2. Objectives Represent curved surfaces in multiview drawings
Show intersections and tangencies of curved and planar surfaces
Represent common types of holes
Show fillets, rounds, and runout in a 2D drawing

3. Objectives (cont.) Use partial views
Apply revolution conventions when necessary for clarity
Draw removed views and projected views
Show right and left hand parts

4. Objectives (cont.) Project curved surfaces by points
Show and label an enlarged detail
Show conventional breaks

5. Common Manufactured Features
Certain features are part of many engineering designs
Learning their names and shapes helps you visualize and communicate about them

6. Common Manufactured Features
Fillet – a rounded interior blend between surfaces
Round – a rounded exterior blend between surfaces
Counterbore – a cylindrical recess around a hole, usually to receive a bolt head or nut

7. Common Manufactured Features
Countersink – a conical-shaped recess around a hole, often used to receive a tapered screw head
Spotface – a shallow recess like a counterbore used to provide a good bearing surface for a fastener
Boss – a short raised protrusion above the surface of a part

8. Common Manufactured Features
Lug – a flat or rounded tab protruding from a surface usually to provide a method for attachment
Flange – a flattened collar or rim around a cylindrical part to allow for attachment
Chamfer – an angled surface used on cylinders to make them easier to handle

9. Common Manufactured Features
Neck – a small groove cut around the diameter of a cylinder, often where it changes diameter
Keyway/Keyseat – a shaped depression cut along the axis of a cylinder or hub to receive a key, used to attach parts to a cylinder so they won’t turn on it

10. Common Manufactured Features
Knurl – a pattern form on a surface to provide for better gripping or more surface area for attachment
Bushing – a hollow cylinder that is often used as a protective sleeve or guide or as a bearing

11. Common Manufactured Features

12. Conventional Representations
Standard orthographic projections don’t always show complex shapes as clearly and simply as you may wish
Simplified conventional representations that deviate from true orthographic projection may be used to enhance economy and clarity in a drawing

13. Intersections and Tangencies
A plane surface can intersect or be tangent to a contoured surface
When a plane intersects a contoured surface, a line is drawn to represent that edge
When a plane surface is tangent to a contoured surface, no line or a thin phantom line is drawn

14. Intersections and Tangencies

15. Removed Views
It is not always possible to show all of the drawing views in alignment on a sheet
When this is the case, a removed view can be used and is indicated by:
A viewing indicator arrow showing direction of sight or
A viewing plane line

16. Removed Views

17. Intersections and Tangencies
Where a curved surface is tangent to a plane surface, no line is drawn
When a curved surface intersects a plane surface, an edge is formed

18. Intersections and Tangencies

19. Intersections of Cylinders

20. Runouts
Small curves called runouts are used to represent fillets that connect with plane surfaces tangent to cylinders

21. Conventional Edges
Because the true projection may be misleading, there is a conventional way of showing rounded and filleted edges for the sake of clarity

22. Partial Views
A view may not need to be complete in order to clearly describe an object
If the view is symmetrical, you can draw a half-view on one side of the centerline

23. Showing Enlarged Details
Enlarged views may be added that show details at a larger scale

24. Conventional Breaks
To shorten the view of a long object, you can use break lines

25. Alignment of Views
Always draw views in a standard arrangement to be sure that the drawings are not misinterpreted
The front view should show the shape of the object clearly

26. Removed Views
A removed view is a complete or partial view removed to another place on the sheet so it is no longer in direct projection with any other view
Removed views show features of an object more clearly
Be sure to label removed views and provide a scale if necessary

27. Removed Views

28. Right-hand & Left-hand Parts
Often parts function in pairs of similar opposite parts
The two parts are mirror images and are not interchangeable
Ordinarily, you draw only one of two opposite parts and label them appropriately

29. Right-hand & Left-hand Parts

30. Revolution Conventions
Regular multiview projections are sometimes awkward, confusing, or misleading
To prevent confusion, features may be revolved to line up vertically and project true length to make symmetry clear

31. Revolution Conventions

32. Common Hole Features

33. Common Features