TPC Reading Blueprints Practice Test

Centerlines are represented by a specific drafting symbol designed to indicate axes of symmetrical objects or locations of holes. This symbol is typically depicted as a long dash followed by a short dash pattern, and collectively, this represents the essential characteristic of a centerline.

In technical drawings, the use of centerlines serves to communicate vital information about the geometric center of an object, which is crucial for manufacturing, assembly, and alignment purposes. Centerlines help machinists and fabricators understand how components should be oriented or aligned during production processes.

While there are other types of lines in drafting, such as dashed lines often used for hidden features and solid lines for visible edges, the distinctive pattern of long and short dashes uniquely identifies a centerline. This clear differentiation is key in conveying the specific function and relevance of the centerline in a blueprint or technical drawing.