Column A
Column B
A. Long break line
B. Dimension line
C. Centerline
D. Invisible line
E. Visible line
F. Borderline

1. The very light line that is used to "block in" an object.
These lines are made so light that little or no erasing is
needed. They serve as a base for darkening in the
permanent line.
2. The heavy, solid line that is used to frame in the
drawing
3. A medium line is used to show edges and contours
visible
4. A medium line that is used to show edges and
contours not visible.
5. A light line that is used as the axis of symmetry.
6. A Light thin line that is used to show the sizes of the
object. Extension lights start about 1/16" from visible
or object line. The dimension line is broken near the
center for the dimension.​