ITMC Blueprint Reading 5 — Questions and Answers
Question 1: On a lubrication diagram, a filled black triangle symbol typically represents:
- A grease fitting or lubrication point (Correct answer)
- A pressure gauge connection
- A drain plug location
- A filter bypass valve
Correct answer: A grease fitting or lubrication point
A filled triangle symbol on lubrication diagrams marks a grease fitting or oiling point where lubricant should be applied.
Question 2: The term 'bilateral tolerance' means that the tolerance is applied:
- Only in a single direction from the nominal dimension
- Equally in both the plus and minus directions from the nominal (Correct answer)
- Differently on each side of the nominal dimension
- Only to features of size, not to location
Correct answer: Equally in both the plus and minus directions from the nominal
Bilateral tolerance distributes the allowable variation equally above and below the nominal dimension, such as ±0.005.
Question 3: On a ladder logic diagram used for PLC programming, a normally closed contact symbol is represented by:
- Two vertical lines connected by a horizontal line
- Two vertical lines with a diagonal slash between them (Correct answer)
- A circle with the letter M inside
- A coil symbol at the end of a rung
Correct answer: Two vertical lines with a diagonal slash between them
A normally closed (NC) contact in ladder logic is shown as two vertical lines with a diagonal slash, indicating it passes current when its coil is de-energized.
Question 4: A break line (wavy or zigzag) on a drawing indicates:
- A theoretical boundary that parts cannot cross
- That a portion of the object has been omitted to save space (Correct answer)
- A fracture or failure point in the material
- The boundary between two different materials
Correct answer: That a portion of the object has been omitted to save space
Break lines indicate that part of the object is not shown, allowing long or repetitive features to be drawn at a larger scale without showing the entire length.
Question 5: In a mechanical assembly drawing, a balloon callout with a number inside refers to:
- The quantity of that part required in the assembly
- The item number corresponding to the parts list or bill of materials (Correct answer)
- The part's drawing revision level
- The sequence of assembly operations
Correct answer: The item number corresponding to the parts list or bill of materials
Balloon callouts on assembly drawings identify parts by their item number, which links to the bill of materials for part numbers, descriptions, and quantities.
Question 6: What does a 'concentricity' GD&T control verify?
- That the surface of a cylinder is within a cylindrical tolerance zone
- That the median points of a cylindrical feature share the same axis as the datum axis (Correct answer)
- That two planar surfaces are parallel within a given tolerance
- That a hole pattern is evenly spaced around a bolt circle
Correct answer: That the median points of a cylindrical feature share the same axis as the datum axis
Concentricity controls the location of the median points of a cylindrical or spherical feature relative to a datum axis.
Question 7: On an electrical one-line diagram for industrial power distribution, a circle with an X inside typically represents:
- A circuit breaker
- A transformer
- A motor or load (Correct answer)
- A metering point
Correct answer: A motor or load
In one-line (single-line) diagrams, a circle with an X inside commonly represents a motor or electrical load connected to the distribution system.
ITMC Blueprint Reading 5
On a lubrication diagram, a filled black triangle symbol typically represents: