ALPHABET OF LINES

ALPHABET OF LINES

A: Visible Object Line (thick)

Visible Object Lines are thick dark solid (unbroken) lines that are used on drawings to indicate the edges and details of an object. These lines should be most prominent on the drawing as they are drawn thicker (wider) than most other lines. A 2H or H lead is generally used to draw visible object lines.

B: Hidden Line (thin)

Hidden Lines are thin dashed lines used to indicate a surface, edge, or contour of an object that cannot be seen, or is hidden from view. A 2H or Hlead is used for drawing hidden lines.

REQUIRED READING: MORE ON HIDDEN LINES HERE

C: Center Line (thin)

Center Lines are thin lines made up of alternating long and short dashes. They are used to indicate the center of symmetrical features and also as an aid in dimensioning. Use 2H or H lead when drawing center lines.

REQUIRED READING: MORE ON CENTER LINES HERE

D: Section Lines (thin)

Section Lines are thin “cross hatching” lines used in sectional views to symbolize different parts of an object or different materials from which an object is manufactured. Use 2H-4H lead when drawing section lines.

E: Dimension, Extension, & Leader Lines (thin)

Dimension, Extension and Leader Lines are thin lines used for dimensioning purposes. Dimension and leader lines generally end with arrow heads and are accompanied by a number indicating a size or location dimension. Extension lines aid dimension lines by extending the surface of the object so it can be dimensioned. Use 2H - 4H lead to dimension an engineering drawing.

F: Cutting Plane or Viewing Plane Lines (thick)

Cutting Plane or Viewing Plane Lines are very thick lines that indicate where an imaginary cutting plane passes through an object, for viewing or sectioning purposes. Arrowheads on both ends of the line point to the surface to be viewed. Use HB-H lead when drawing cutting plane lines.

G: Break Lines (thick or thin)

Break Lines are used to shorten a view, or to eliminate repetitive details when an entire view is not necessary. Short break lines are thick wavy freehand lines. Long break lines are thin straight zig-zags.

H: Phantom Line (thin)

Phantom Lines are thin lines used to indicate alternate positions of moving parts, lines of motion, adjacent parts and repetitive details. They are similar in style to a Cutting Plane Line but much thinner in weight.