Alphabet of Lines

Alphabet of LinesIntroduction to Drafting and Design

In this presentation, we are going to learn about the different lines that are used in a drawing. The list of different lines is known as the alphabet of lines1What is the Alphabet of Lines?Developed by the American Society of Mechanical Engineers (ASME).The Alphabet of Lines is used to make a drawing neater and clearer to understand.Different lines represent different aspects of a drawing.

So what is the Alphabet of Lines?The alphabet of lines was developed by the American Society of Mechanical Engineers and is used by all drafters and engineers today. It is used to make a drawing neater and clearer to understand.Different lines represent different aspects of a drawing.

2So what are these lines?

Construction LinesVisible/Object LinesHidden LinesCenter LinesDimension LinesExtension LinesPhantom LinesLong Break LinesShort Break LinesCutting-plane LinesSection LinesChain LinesLeadersSymmetry LinesBorder Lines

So what are these lines that are considered the Alphabet of Lines?Construction linesVisible/object linesHidden linesCenter linesDimension linesExtension linesPhantom linesLong break linesShort break linesCutting-plane linesSection linesChain linesLeadersSymmetry linesBorder lines

3Construction LinesUsed to initially lay out a drawings.Used for guidelines for lettering.Drawn very light and thin so that they are barely visible.

Construction linesUsed to initially lay out a drawingUsed for guidelines for letteringDrawn very light and thin so that they are barely visibleThey should be drawn so light that they dont have to be erased once the drawing is complete.

4Visible/Object LinesUsed to represent the visible edges of an object.Should be the most prominent on the drawing.Drawn thick and dark.These are thicker than construction lines.

Visible/object linesUsed to represent the visible edges of an object.Should be the most prominent on the drawingDrawn thick and darkThese are thicker than construction lines.

5Hidden LinesUsed to represent edges, surfaces or corners of an object hidden from view.Drawn as thin, dark dashed lines.Spacing can vary slightly.Only the most important hidden parts are shown on the drawing to keep the drawings from becoming cluttered.

Hidden LinesUsed to represent edges, surfaces or corners of an object hidden from view.Drawn as thin, dark dashed linesSpacing can vary slightlyOnly the most important hidden parts are shown on the drawing to keep the drawings from becoming cluttered.

6Center LinesUsed to show the center of circles and arcs.Drawn as thin lines.Drawn using two long dashes and a shorter dash.To show the center of a round object, two centerlines are used so that the short dashes cross in the center.

Center linesUsed to show the center of circles and arcsDrawn as thin linesDrawn using two long dashes and a shorter dashTo show the center of a round object, two centerlines are used so that the short dashes cross in the center.

7Dimension LinesUsed for dimensioning and notes.Drawn as thin lines.Drawn with arrowheads on each end and placed between extension lines.The dimension is lettered above the dimension line approximately half way between the two extension lines.

Dimension linesUsed for dimensioning and notesDrawn as thin linesDrawn with arrowheads on each end and placed between extension linesThe dimension in lettered above the dimension line approximately half way between the two extension lines.

8Extension LinesUsed to extend dimensions from the related objects.Drawn as thin lines.Drawn with a short space between the object and line.Extend about 3 mm beyond the dimension line.

Extension linesUsed to extend dimensions from the related objectsDrawn as thin linesDrawn with a short space between the object and line.Extend about 3 mm beyond the dimension line

9Phantom LinesUsed to show objects that are not hidden but they are simply not in view.Also used to indicate alternate positions of moving parts, lines of motion, adjacent parts and repetitive details.Drawn as thin, dark lines.

Phantom linesUsed to show objects that are not hidden but they are simply not in viewAlso used to indicate alternate positions of moving parts, lines of motion, adjacent parts and repetitive detailsDrawn as thin, dark lines

10Long Break LinesUsed to indicate parts of the object has been removed.Used when it is desirable to shorten the view of a long part.Long break lines are drawn thin with freehand zigzags.

Long break linesused to indicate parts of the object has been removedused when it is desirable to shorten the view of a long partlong break lines are drawn thin with freehand zigzags

11Short Break LinesUsed to indicate parts of the object has been removed.Used when it is desirable to shorten the view of a long part.Short break lines are drawn thick and with freehand wavy lines.

Short break linesUsed to indicate parts of the object has been removedUsed when it is desirable to shorten the view of a long partShort break lines are drawn thick and with freehand wavy lines

12Cutting-plane LinesUsed to indicate the plane through which a cut was made.A cutting plane line is usually a heavy line with long dashes with arrowheads at both ends of the line.The arrowheads point to the surface to be viewed.

Cutting-plane linesUsed to indicate the plane through which a cut was madeA cutting plane line is usually a heavy line with long dashes with arrowheads at both ends of the lineThe arrowheads point to the surface to be viewed

13Section LinesUsed to indicate the surface in the section view imagined to have been cut along the cutting plane line.Thin cross hatching lines drawn at a 45 angle.

Section linesUsed to indicate the surface in the section view imagined to have been cut along the cutting plane lineThin cross hatching lines drawn at a 45 angle

14Chain LinesUsed to indicate an area or portion of a surface that is to receive special treatment.Represented by a long dash followed by a short dash followed by a long dash.

Chain linesUsed to indicate an area or portion of a surface that is to receive special treatmentRepresented by a long dash followed by a short dash followed by a long dash

15LeadersUsed to point to notes or dimensions.Drawn as thin lines.Consist of an arrowhead and angled line connected to a surface.Arrowheads touch the object lines while the dot rests on a surface.

LeadersUsed to point to notes or dimensionsDrawn as thin linesConsist of an arrowhead (or dot) and angled line connected to a surfaceArrowheads touch the object lines while the dot rests on a surface

16Symmetry LinesUsed when partial views of symmetrical parts are drawn.It is a center line with two thick short parallel lines drawn at right angles to it at both ends.

Symmetry linesUsed when partial views of symmetrical parts are drawnIt is a center line with two thick short parallel lines drawn at right angles to it at both ends

17Border LinesUsed to outline the entire drawing.They are a continuous thick line on the outer rim of the paper.

Border linesUsed to outline the entire drawingThey are a continuous thick line on the outer rim of the paper

18Lets look again

Lets take a look again at the picture that appeared at the beginning of this presentation19Hierarchy of LinesIf lines happen to overlap, then there is a hierarchy to which the lines show up.The hierarchy of lines is as follows:Object or visible lineHidden lineCutting Plane lineCenter lineBreak lineDimension and extension linesSectioning lines

Hierarchy of LinesIf lines happen to overlap, then there is a hierarchy to which the lines show upThe hierarchy of lines is as follows:Object or visible lineHidden lineCutting plane lineCenter lineBreak lineDimension and extension linesSection lines

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