draw 111- mechanical drawing and orthographic drawing

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and Standard Operating Procedure Procedure in Setting up Drawing tools, Materials and Equipment

Before starting the drawing activity: Select the tools, materials and equipment which are needed in the assigned task. Properly set up the required tools and materials in a place which is convenient for you to move and execute your work. Clean the table and tools, see to it that these are free from the dust and other elements that would cause damage to your work. Wash your hand with clean water.

Activity proper: Perform the activity by following the standard operating procedure per job requirement. Properly manipulate all the tools and equipment that are used in the activity. In case of meeting an errors or mistakes along the way of activity ( for instance misprinting of lines, letters, and other forms of mistakes) use appropriate eraser for a particular mistakes.

After the activity: Submit your output to your teacher for checking Check all the tools and materials to ensure that nothing has lost. Return the tools and materials to the assigned tool keeper for safekeeping. Clean your work station before leaving.

Alphabet of LinesLines in technical drawing are represented as follows: According to weightThickMediumThinAccording to constructionContinues lineBroken and dashed lineCombination of continues and broken/dashed line

According to meaning or use

Border lines are generally the heaviest or the darkest lines in a drawing. The border surrounds a drawing and is usually rectangular in shape. It makes the onlooker feels as if the parts of the drawing are combined into a single unified graphic representation.

Visible lines this is used to show the outlines and corners that can be seen when the object is viewed. It is often called as the object lines.

Hidden lines this is used to show the edges that are not normally seen when the object is viewed.

Dimension lines this is a line terminated by arrowheads at each of its end, it is used to indicate the direction and extent of measurements. Along this line is a numerical value indicating the units of measurements. Extension lines this is lines that extends from a point in the drawing to which the dimension refers and meets the dimension line at the right angle.

Center line this is used to indicate the center of a circle or arc, or to indicate the axis of an object with circular features.

Leader Line a thin solid line leading from a dimension value or a note to the part on the drawing to which the note applies. An arrowhead is used to point the leader, but never on the note end. The end note of the leader should end with a short horizontal bar at the mid-height of the lettering and should runeither to the beginning or end of the note.Leader Line

Cutting plane lines this lines are used to indicate an imaginary cut through an object along the line. It is made with long heavy dashes alternating with two short dashes. Section lines this are light lines used in making sectional views. They are spaced evenly to make a shaded effect.

THEORIES AND PRINCIPLES OF ORTHOGRAPHIC PROJECTIONThe term orthographic came from the Greek word orthos and graphos which meansstraight line drawing.Planes of ProjectionFrontal Plane this shows the shape of an object when viewed from the front. This is known as the Front View of the object.

Horizontal Plane this give the appearance of the object as if viewed directly from above.It shows the distance from the front to the rear.This is known as the Top View of an object.Profile Plane this shows the shape of the object when viewed from the side. The distancefrom bottom to top and front to rear also appears.It is known as the Side View of an object.

When opening the planes that forms a box or is sometimes called imaginary box, the six views of the object are represented on the following positions as shown below.

Top ViewFront ViewBottom ViewRear ViewLeft Side ViewRight Side View

FRONT VIEW: Height and WidthTOP VIEW: Width and DepthRIGHT VIEW: Depth and Height

Principles of Orthographic DrawingThe front view and top view are always drawn in line vertically. Align views with each other (features project from one view to the next)

2. The front and the right side view are always drawn in line horizontally.

8. A line projected perpendicularly to the plane of projection, its projection on the plane will be a line.

13. The front of the object in the side view faces the front view.3. The height of the front view is the same as height of the right side view.4. The depth of the top view is the same as the depth of the side view.6. A view taken from above is a top view and must be drawn above the front view.7. A view taken from below is a bottom view and must appear below the front view.9. A line when projected parallel to the plane of projection, its projection will be a line.10. An inclined line projected to the plane of projection, its projection on the plane will be foreshortened.11. A view from the right, is a right-side view and must be drawn left of the front view.12. The front view of the object in the top view faces the front view.

Plan View or Top View This can be little more difficult to visualize because you have to imagine yourself moving over the top of the object and looking vertically downward. The left-hand and right-hand illustration shows how the plan is placed above the front. Again, sketch the light vertical construction lines to locate the plan in its proper position. Draw these upward from each corner of the front view.

Front View Concentrate on the front view. If you look at it correctly the effect will be seen below at the left, while at the right illustration shows what you will actually see. Notice that in the left-hand drawing, you can only see the dark-inked front face of the object. Notice also that you cannot see any of the other sides of the object. This is because all those sides are going away from you in your line of sight and are simply not visible from your view point. They are still there, of course, but are hidden behind the outer edges of the first face.

Right-Side View

Right-side view should be drawn at the right side of front view. Imagine moving around the object to look directly at its right side. How you see it is shown below-left and what you see is shown below-right. Again the faces you actually see are heavily outlined.

Procedure in Constructing Orthographic Views

1. Analyze the given object.

2. Draw the proper construction line where the three regular view of the orthographic projection will be designated.


3. Start focusing at the frontal plane of the object to obtain the necessary details of the front view.

Consider the height and length of the object in constructing the front view. Draw the height details using construction lines.

4.Draw the length details of front view. Extend the construction lines to the position of the plan considering that the front view and the plan share the same length as stated in the principles of orthographic drawing.

5. Draw the object lines base on the intersection of the construction lines of step 3 and step 4.

6. Provide a distance of not less than 20mm on top of the front view to start the construction of the plan. Draw the depth details of the object since the length details are already in place. Use construction lines in doing this step

7. Draw the object lines base on the intersected of the construction lines that corresponds to the details of the object.

8. Provide a 45 angle line that extends from the edge of the front view towards the side of the plan.

The 45angle line will serve as a pivotal point of the lines that have intersected it coming from the depth details of the plan. Lines that are intersected will be projected towards the Position of the right side view which will provide the same depth of the right side view. Use construction lines in doing this step.

9. Draw the object lines base on the intersected of the construction lines that corresponds to the details of the object.

10. Provide the necessary labels,

and dimensions of each of the views.


Drawing Exercises: Base on the given drawings, construct the three principal views following the principles in constructing orthographic drawing. Utilize the proper type of lines in accordance with its use.


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