Blueprint Reading & Specifications Flashcards

In blueprint reading, what does a centerline symbol (CL or ℄) signify?

Answer: The axis of symmetry or center of a feature such as a hole or shaft

Centerlines mark the axis of symmetric features and are used to locate holes, shafts, and similar elements.

Which specification writing method describes the desired result or performance level without specifying a particular product?

Answer: Performance specification

Performance specifications state what the finished product must achieve, leaving the means to the contractor.

On a structural drawing, what does 'W12×53' describe?

Answer: A wide-flange steel beam, 12 inches nominal depth, weighing 53 pounds per linear foot

The 'W' designation denotes a wide-flange shape; the first number is nominal depth in inches and the second is weight per foot.

What does the symbol 'Ø' preceding a dimension number indicate on a mechanical drawing?

Answer: The feature is a diameter

The Ø symbol indicates that the dimension refers to the diameter of a circular feature.

In the CSI three-part specification format, Part 2 covers:

Answer: Products, materials, and their standards

Part 2 (Products) specifies the materials, components, and manufactured items to be used.

On a site plan, contour lines that are close together indicate:

Answer: Steep slope or rapid elevation change

Closely spaced contour lines mean elevation changes rapidly over a short horizontal distance, indicating steep terrain.

What is the purpose of a 'break line' on a technical drawing?

Answer: To show that a long or repetitive object has been shortened to fit the drawing sheet

Break lines allow long uniform objects to be represented at a larger scale by omitting the middle section.