Technical Drawing & Blueprint Interpretation Flashcards

In an exploded assembly drawing, leader lines and part numbers are used to:

Answer: Identify each component and reference the parts list or BOM

Balloons with part numbers on leader lines key each component to the bill of materials (BOM) for identification and procurement.

A 'datum' in GD&T is best described as:

Answer: A theoretically exact point, axis, or plane from which measurements are made

A datum is a theoretically perfect geometric reference (point, line, or plane) established from actual datum features for measurement purposes.

What does the abbreviation 'REF' next to a dimension on a drawing mean?

Answer: The dimension is for reference only and is not to be used for fabrication

A reference dimension (REF) is shown for information only and does not control manufacturing; it is derived from other dimensions.

On an architectural floor plan, a dashed rectangle inside a room typically represents:

Answer: A skylight or ceiling feature above the cut plane

Features above the horizontal cutting plane, like skylights, ceiling beams, or upper cabinets, are shown with dashed lines on floor plans.

When a drawing callout reads 'Ø25 ±0.05', the maximum allowable diameter of the feature is:

Answer: 25.05 mm

The upper limit is the nominal plus the positive tolerance: 25.00 + 0.05 = 25.05 mm.

In a welding symbol on a technical drawing, the arrow side of the reference line indicates:

Answer: The weld is applied on the same side of the joint as the arrow

Weld symbols placed below the reference line indicate an arrow-side weld, meaning the weld is made on the surface the arrow points to.

Which drawing view is created by rotating a cross-sectional cut 90° and placing it within the outline of the original view?

Answer: Revolved section

A revolved section is created by revolving the cross-section 90° and superimposing it in place within the original view using thin solid or break lines.