Welding Blueprint reading

Object line

Shows visable edges and contour of an object, heavy solid line

Hidden line

Shows hidden features of an object, broken line medium weight

Center line

Shows the axes of symmetrical parts and aid in dimensioning, fine broken line consisting of alternating long and short dashes

Extension line

Used to show the termination of a dimension, solid fine line

Dimension line

Indicated the extent and direction of dimensions, fine solid line terminated with arrow heads

Cutting plane or viewing plane

Used to indicate the location where an imaginary cut is made through an object and the viewing position removed. The arrow heads point in the direction that the piece should be viewed from, heavy line consisting of alternating long dashes and a pair of short dashes or of equal dashes. Both terminated with arrowheads

Short break line

Used to indicate a short break on a partial section of an object in order to conserve space on a drawing, heavy irregular freehand line

Long break line

To show long breaks, light ruled line with freehand zigzags

Phantom line

Shows adjacent parts, alternate positions, and lines of motion. Thin lines composed of long dashes alternated with pairs of short dashes

Section lines

Used to show cut surfaces of an object, thin slanting lines

Leader

Used to point to a surface for the purpose of dimensioning or adding a note, fine line with an arrowhead on one end