What does a check mark mean on a blueprint?

Sometimes only certain surfaces of a part need to be finished while others are not. A modified symbol (check mark) with a number or numbers above it is used to show these surfaces and to specify the degree of finish required.

What are tolerances in blueprints?

A tolerance is an acceptable amount of dimensional variation that will still allow an object to function correctly. Three basic tolerances that occur most often on working drawings are: limit dimensions, unilateral, and bilateral tolerances.

What are the dimensioning rules for architectural drawing?

Each dimension should be written clearly with only one way to be interpreted.

  • A feature should be dimensioned only once.
  • Dimension and extension lines should not cross.
  • Each feature should be dimensioned.
  • Dimension features or surfaces should be done to a logical reference point.

    • What are phantom lines in blueprints?

    Phantom Line Phantom lines are long-short-short-long lines most often used to show the travel or movement of an object or a part in alternate positions. It can also be used to show adjacent objects or features.

    Where tolerances can be found on a blueprint?

    The tolerance block, sometimes referred to as the general tolerance block, is usually located in the bottom right or bottom middle section of the blueprint. The tolerance block identifies the tolerances associated with dimensions that are not directly listed on the drawing.

    How do you read tolerance?

    How To Read Tolerances

    1. As direct limits or tolerance values applied directly to a dimension.
    2. Through geometric representation of the part.
    3. With notes referring to specific conditions.
    4. With plus/minus symbols next to a measurement (for example, 22” + . 02”)

    What is the recommended spacing between dimension lines?

    Dimension lines should be spaced uniformly throughout the drawing. They should be at least 3/8″ from the object outline and 1/4” apart. 13. No line of the drawing should be used as a dimension line or coincide with one.

    What do narrow lines mean in diagrams?

    Hidden Lines (Thin) These lines are drawn to represent hidden or invisible edges of the objects.

    What do phantom lines indicate?

    Phantom lines are used to indicate imaginary features such as alternate positions of moving parts and adjacent positions of related parts. The line type is long dash – short dash – short dash and the line weight is usually thin (0.3 mm).