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So the rule of thumb would be, yes, you need them for dimension purposes but you also need them for dimensioning purposes if there is more than one feature all along that centerline. So, if there is more than one feature along the centerline you do have to show them on your drawing.
What is the purpose of a center line?
a line along the center of a road or highway dividing it into separate sections for traffic moving in opposite directions.
What are the do’s and don’ts of dimensioning?
1. Each dimension should be given clearly, so that it can be interpreted in only one way. 2. Dimensions should not be duplicated or the same information be given in two different ways, and no dimensions should be given except those needed to produce or inspect the part.
Why is it important that the dimension figure should be located at the center of the dimension line?
It indicates direction and extent of a dimension. In machine sketches and drawings, in which fractions and decimals are used for dimensions, the dimension line is usually broken near the middle to provide open space for the dimension numerals.
Why hidden lines and center lines are used?
Hidden lines in a drawing represent the edges where surfaces meet but are not directly visible. Hidden lines are omitted from pictorial drawings unless they are needed to make the drawing clear.
What is centerline in engineering drawing?
Centerlines are one of the most frequently used tools in engineering drawing. Their basic purpose is to show circular/cylindrical features in a drawing, which are found in abundance in mechanical parts. Centerlines indicate a circular feature on a drawing.
What is center line in drawing?
Center lines denote a circular feature such as a shaft or a hole. A rectangular feature seen on an elevation of a drawing could be identified either as a circular feature or a rectangular feature. The center line is the method of quickly identifying the shape.
What are the rules of dimensioning drawing?
Dimension lines should be spaced uniformly throughout the drawing. They should be at least 3/8″ from the object outline and 1/4” apart. 13. No line of the drawing should be used as a dimension line or coincide with one.
What are the dimensioning rules for architectural drawing?
Each dimension should be written clearly with only one way to be interpreted. A feature should be dimensioned only once. Dimension and extension lines should not cross. Each feature should be dimensioned. Dimension features or surfaces should be done to a logical reference point.
What is the difference between the section line and the Centre line?
Centre lines are drawn to indicate the exact centre of a component being drawn. They are made from a series of lighter long and short dashes. Section lines are special lines placed on a drawing which indicate the area of the drawing through which an imaginary cut has been made to reveal internal details.
What is the necessity of dimension a drawing?
The purpose of dimensioning is to provide a clear and complete description of an object. A complete set of dimensions will permit only one interpretation needed to construct the part. Dimensioning should follow these guidelines.
What are the two systems of placing dimensions on a drawing illustrate your answer with sketches?
Explanation: The two systems of placing dimensions are aligned system and unidirectional system. In the aligned system, the dimension is placed perpendicular to the dimension line. In the unidirectional system, all dimensions are placed such that they can be read from the bottom of the drawing sheet. 2.
Which of the following Cannot be drawn accurately using roll and draw?
Explanation: Roll-N-Draw is used to draw lines, parallel lines, circles, and angles. Continuous curves are drawn using French curves. Hence using roll-n-draw we cannot accurately draw continuous curves.
Do you draw hidden lines in isometric drawings?
Usually only the visible surfaces of an object are drawn in isometric, with hidden lines left out. Although this is considered the preferred practice, there are always times when hidden lines are needed to clarify very complex isometric drawings.
Why do you need to draw projection lines when making an orthographic projection drawing?
The Miter Line and Projection Lines The use of a 45° miter line and Projection Lines provide a quick, accurate method of drawing the other views once one view is completed. Sometimes you will need to work on separate views and project lines to each other to fully complete any view.
What line is used as center line?
Center lines are used to indicate the centers of holes, arcs, and symmetrical objects. They are very thin (size), long-short-long kinds of lines. Dimension lines are thin and are used to show the actual size of an object. There are arrowheads at both end that terminate at the extension lines.
Which rules should he follow for the placement of dimensions?
Overall dimensions should be placed the greatest distance away from the object so that intermediate dimensions can nest closer to the object to avoid crossing extension lines. 9. A dimension should be attached to only one view (i.e., extension lines should not connect two views). 10.
What are the basic rules of dimensional analysis?
The most basic rule of dimensional analysis is that of dimensional homogeneity. Only commensurable quantities (physical quantities having the same dimension) may be compared, equated, added, or subtracted.
Where should the scale be on a drawing?
The scale is shown as the length in the drawing, then a colon (“:”), then the matching length on the real thing. Example: this drawing has a scale of “1:10”, so anything drawn 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.
When drawing a floor plan what is drawn first?
There are a few basic steps to creating a floor plan: Choose an area. Determine the area to be drawn. Take measurements. If the building exists, measure the walls, doors, and pertinent furniture so that the floor plan will be accurate. Draw walls. Add architectural features. Add furniture.
How do you read architectural dimensions?
Room dimensions are presented in width by the length. For example, a room that has a dimension of 12′ x 16′ means it’s 12 feet wide (from side to side) by 16 feet long (from top to bottom). Rooms aren’t always square, so make sure you understand fully how the room feels.
Why is oblique drawing used?
Oblique projections Oblique drawings are not very realistic as it is impossible to see the front of an object straight on and the side at the same time. They can be useful to sketch at speed or to show the front and side of a building.
Which line on a drawing should be the thickest?
The direction of the cutting line is shown with a line called a cutting plane lineHeavy dashed line that shows a theoretical cut through an object.. This is the thickest line that may appear on a drawing.
Why do you think alphabet of lines are important in kitchen layout plans?
Technical drawings provide clear and accurate information how an object is to be manufactured. Line symbols used in technical drawing are often referred to as ALPHABET OF LINES. The use of line symbols enables engineers/designers to express the features of designed products clearly and accurately.
