Engineering Drawings. Engineering Drawing and Sketching. By Ernesto E.
Blanco, David Gordon Wilson, Sherondalyn Johnson, and LaTaunynia Flemings Engineering Drawing Index Introduction One of the best ways to communicate one's ideas is through some form of picture or drawing. This is especially true for the engineer. We will treat "sketching" and "drawing" as one. This is just an introduction. We hope you like the object in Figure 1, because you'll be seeing a lot of it. Isometric Drawing The representation of the object in figure 2 is called an isometric drawing. Any engineering drawing should show everything: a complete understanding of the object should be possible from the drawing. Orthographic or Multiview Drawing Imagine that you have an object suspended by transparent threads inside a glass box, as in figure 3. Then draw the object on each of three faces as seen from that direction.
Figure 5 shows how the three views appear on a piece of paper after unfolding the box. Which views should one choose for a multiview drawing? Dimensioning. Drawing Guide/ BS8888 details. Projections First angle and third angle projection methods are acceptable.
The symbol identifying the type of projection used should be placed in a space provided in the drawing block Views Using Reference Arrows. Principal View The principal view on which all of the other views are based should be selected as being the most informative. Lines Used on Drawings.. Line Thicknesses Two thicknesses of line should be used on a drawing. Line spacing The minimum space between parallel lines should always be greater than twice the thickness of the heaviest line.
Leader Lines Leader Lines terminate Lettering Lettering should all be in capitals and underlining should be avoided. With the normal paper in landscape orientation and the title block on the bottom right and side, notes to be parallel with the bottom edge. General notes shall be normally grouped together. Metrics in Drafting. Guide to engineering Drawing. First Angle & Third Angle Projection - Engineering Wave. First Angle Orthographic Projection.
Basic Drawing Equipment - 1 2. Basic Drawing Equipment - 2 3. Basic Drawing Equipment - 3 4. 5. 6. 7. Basic Drawing Test Improving the Standard of Presentation of Design Sheets - 1 Improving the Standard of Presentation of Design Sheets - 2 1. 2. 3. 4. 5. 6. 3D drawing using a 30/60Degree Set Square 7. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Thick and Thin Line Emphasis - Shading Technique Thick and Thin line Emphasis - Using Colour Thick and Thin Lines and Hatching Technique Thick and Thin Lines AND Background Highlighting with Felt Pens Thick and Thin Lines AND Backgrounds with Coloured Pencils. Third Angle Orthographic Projection - Further Explanation. What do we mean by perspective? Perspective drawings show objects as you would see them in the real world - in three dimensional view.
Have a look at the perspective drawing below. Three sides of the cube are visible so it appears to be three dimensional even though it is drawn in a two dimensional plane. The lines of sight in a perspective drawing can be projected to a vanishing point in the distance. This is what gives the appearance of depth. Perspective drawings are a 3D representation of an object but the proportions are not true – they are distorted to give the perception of depth.
Disadvantages of a perspective drawing Only three sides of a component are shown. Due to these disadvantages, engineering drawings are rarely drawn in perspective projection. What is third angle orthographic projection? In Australia third angle projection is the preferred method for orthographic projection drawing as recommended by the Australian Standard 1100 Part 101.
Note the symbol for third angle projection. This is important information for the person interpreting the drawing because in third angle projection: the view from the front is in the middle the view from the left is on the left the view from the right is on the right the view from the top is on the top the view from the bottom is on the bottom the view from the rear is on the far right.