Drafting Unit 1

Lines that are used to show measurement...

4A. Extension lines: These lines are used to illustrate the absolute boundaries that represent various sections of the object. Extension lines never make contact with the outer boundary of the object. 4B. Dimension lines: These lines are used in conjunction with extension lines to give the true size of a particular section in the drawing.

Center Lines

Center lines are used to illustrate the center of holes or the symmetry of an object.

Leader Lines

Leader lines give specific information about a particular part of the object it is pointing to. The information could be in the form of a note of some kind or even simple numerical data.

Phantom Lines

Phantom lines are used to indicate the movement of an object in a drawing. The original part of the object is drawn using standard object lines where as the alternate position are drawn using phantom lines.

Break Lines

These lines are used in situations when drawing a part of an object in its entirety is unnecessary. Break lines are used after the objects signature features have been shown.

Hidden Lines

These lines are used to illustrate the various surfaces, edges ,corners, or sections of an object that would normally not be seen.

Section Lines

These lines are used to indicate when an object has been sliced. Section lines will appear as angled line patterns that are usually drawn at Forty-five degrees. Section lines are drawn only at areas that have been virtually cut by the cutting-plane.

Object Lines

These lines represent the outer body of an object: Object lines otherwise known as visible lines shows all the visible edges of an object in the drawing. These lines are always the darkest lines in the drawing.

Cutting-Plane Lines

This line is used to show sectional views of a drawing. Cutting-plane lines also designate where the imaginary slicing of that object took place.