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Line Conventions. Line Conventions. A drawing should convey as much information as the physical object (if not more). Following standards ( e.g . line conventions) minimizes confusion and miscommunication. Fabricators should be able to make your design based solely on your drawing.
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Line Conventions • A drawing should convey as much information as the physical object (if not more). • Following standards (e.g. line conventions) minimizes confusion and miscommunication. • Fabricators should be able to make your design based solely on your drawing. Make a table of three columns
Object Lines • Object lines are thick, solid lines. • Used to show visible edges or outlines of objects. Fill in the first row of your table
Hidden Lines • Thick, dashed lines. • Used to show edges not visible in that view. • Dashes are short and evenly-spaced. • Dashes start and end in contact with the object line.
Construction Lines • Very Thin, Solid line. • Used as an aide in drawing and to line up views. • Should be barely visible; disappear if squint or photocopy. “Never” erase construction lines
Center lines • Thin, with long and short dashes. • Used to indicate center of a circle, arc, or any symmetrical object. • Dashes alternately and evenly spaced, with a long dash at each end. • Short dashes cross at intersecting points.
Dimension lines • Thin lines terminating in arrowheads, broken in center for the dimension figure. • Used to show size or location. • Dimension lines are not on object. • Dimension lines can’t touch object.
Extension lines • Thin solid with a 1/16" gap (to avoid confusion with object lines). • Used to define the extent of dimensions. • May cross other extension lines. • Can’t cross dimension lines.
Leader lines • Thin, solid lines that end in an arrowhead or dot. • Used for notes or dimensions (e.g. diameter of circle). • Arrowheads to outline. • Dot to surface of object.
Long Break Lines • Very thick, Zigzag lines • Used to save space when you have a long object of continuous shape and size. • Called break lines because you figuratively break away an unimportant segment of an object. • Shorten very long objects with uniform detail. Typically represented as a jagged cut or break
Short Break Lines • thick, solid (and/or wavy) freehand lines. • Used to indicate a short break in an object, • Rods, tubes, and bars have additional conventions that not only break their length but also imply the material or texture of the object.
Viewing or Cutting Plane Lines • Thickest of all lines, dashed with bent arrows. • Viewing lines used to give a clearer view of obscure or oblique planes. • Cutting plane lines used to show interior or hidden features that cannot be clearly observed from outside.
Viewing or Cutting Plane Lines • Cutting plane lines, together with arrowheads and letters, make up the cuttingplane indications. • Arrowheads indicate the direction from which you view the section. • Cutting plane may be a simple, continuous plane, or it may be offset to show the interior detail to better advantage.
Phantom or Datum Lines • Medium weight series of one long dash and two short • Used to indicate alternate positions of parts, repeated detail, or to indicate a datum plane. • Dashes are evenly spaced and terminate in a long dash.