Quick Answer: Can Centerlines Be Used As Extension Lines?

What are alphabet lines?

The Alphabet of Lines is a list of line symbols that engineers use in technical drawings to communicate specific shapes, sizes or surfaces.

The lines and symbols used in the Alphabet of Lines are universal, which means engineers around the world use and understand them..

What is double dimensioning?

Dual dimensioning is the drafting practice of using multiple units of measure in a dimension in the same direction of a feature.

What is the purpose of leader line and extension line?

Extension lines are also thin lines, showing the limits of dimensions. Dimension line arrowheads touch extension lines. Leaders are more thin lines used to point to an area of a drawing requiring a note for explanation. They are preferably drawn at a 45° angles.

What is the difference between dimension lines and extension lines?

Dimension & Extension Lines. Dimension Lines – show the direction and extent of the numerical size. They are thin lines and terminate with an arrowhead at each end. … Extension Lines – are used to extend a surface or a point beyond the outline of the object so that a numerical size can be related to that surface.

Which should never be used as a dimension line?

Explanation: An outline or a centre line should never be used as a dimension line. A centre line may be extended to serve as an extension line.

What are the three types of centerlines?

Line ConventionsCenter lines. Center lines are used to indicate the center of a circle, arc, or any symmetrical object. … Visible Lines. The visible edge lines of the view are drawn as solid, thick lines. … Hidden Lines. … Extension Lines. … Dimension Lines. … Leaders. … Break Lines. … Phantom Lines.More items…•

What are extension lines?

Extension lines continue or extend from the surface of the object and establish the size of the dimension. They do not touch the object lines and extend slightly past the dimension line. Extension lines provide a means of displaying a measurement without placing the dimension on the part.

What four lines are used to aid in dimensioning?

There are four methods: parallel, running, chain, and combined dimensioning. Some methods of dimensioning a drawing can create an accumulating error.

What is the heaviest line in a drawing?

The heaviest line weight indicates spatial edges. Medium line weight indicates planar corners, where two or more planes intersect. Light (and very light) line weight is used to indicate surface lines (material, pattern, or texture).

Is the softest pencil used in engineering drawing?

Pencil is used to draw on the paper….Pencils.Grade of PencilHardness of Pencil7BSoftest11 more rows

Can you dimension to a centerline?

Dimensions should be given to finished surfaces or between important center lines (not to rough surfaces) wherever possible.

What are the 8 rules of dimensioning?

Terms in this set (8)Rule 1: Dimensions should not be duplicated, nor should the same info be given in two different ways.Rule 2: Dimensions should be attached to the view that best shows the contour of the feature being dimensioned.Rule 3: … Rule 4: … Rule 5: … Rule 6: … Rule 7: … Rule 8:

What are short break lines?

Short break lines are thick, wavy solid lines that are drawn freehand. When either of these break lines is used to shorten an object, you can assume that the section removed from the part is identical to the portions shown on either side of the break.

What are leader lines?

A leader line is a line that establishes a connection between a graphical representation of an item and some text. A leader points to a bit of our drawing and says: … A leader line also has a terminator and some text. A leader line may have a reference line under the text.

Are leader lines always horizontal?

Leaders should make a large angle (30° to 60°) with the line they touch. Leaders should never be horizontal or vertical. 28. Leader lines should never cross one another, nor should they be parallel or nearly parallel to nearby dimensions, extension, or cross-hatching lines.

What does dimensioning of a circle depends upon?

Explanation: The dimensioning of the circle depends upon the size or diameter of the circle. If the diameter of the circle is considerably large, the dimension can be given inside the circle itself. It should be noted that the dimension of the circle should be given in the view where its true shape is visible.

Can extension lines cross dimension lines?

No line of the drawing should be used as a dimension line or coincide with one. … Dimension lines and extension lines should not cross, if avoidable. Extension lines may cross each other. When extension lines cross extension lines or visible lines, no break in either should be made.

What does an extension line look like?

Furthermore, what does an extension line look like? Extension lines indicate the points between which the dimension figures apply. They are drawn perpendicular to the dimension lines, start with a visible gap (~1/32″) between them and the object, and terminate 1/8″ (3.2 mm) beyond the last arrowhead.