A | B |

Dimension lines | Terminated by arrowheads |

Dimension lines | Shows the beginning and the end of the measurement |

Dimension lines | Thin line weight |

Dimension lines | Should be broken to allow for the numbers to be inserted |

Dimension lines | minimum of 3/8" away from the object |

Dimension lines | minimum of 1/4" away from parallel dimension lines |

Extension lines | 1. Extend the edge of the object |

Extension lines | Thin line |

Extension lines | 1/16" gap between the object and the start of the extension line |

Extension lines | Extend about 1/8" beyond the last dimension line |

Leaders | Are drawn at an angle (usually 30°, 45°, or 60°). |

Leaders | have a short (1/8") shoulder |

Leaders | end with an arrowhead |

Leaders | should not cross over dimension lines |

Leaders | Avoid making parallel or perpendicular to visible edges |

Leaders | extend from the first word or the last word of the note |

Arrowheads | Can be solid filled or open |

Arrowheads | 1/8" long |

Arrowheads | 3 times as long as wide |

Fractional inches | Used where close tolerances are not important |

Fractional inches | The fraction bar is horizontal |

Fractional inches | Omit the inch mark |

Metric | millimeter is the standard unit of measure |

Metric | abbreviation for millimeters (mm) is usually omitted |

Metric | 4. If the value is less than one millimeter, a zero should precede the decimal point |

Decimal inches | Omit zero before the decimal point for values of less than one |

Decimal inches | should be rounded to two decimal places |

Decimal inches | the ANSI standard |

clarity | number one rule of dimensioning |

dimensions | placed where the shape is best shown |

dimensions | Shortest placed closest to the object |

dimensions | Group and align when possible |

dimensions | 5. Avoid duplicate and/or unnecessary |

dimensions | Do not place to coincide with a line of a drawing |

dimensions | Avoid crowding |

dimensions | avoid placing inside a view |

dimensions | Avoid hidden features |

dimensions | Place between views to which they relate |

dimension lines | thin and dark |

dimension lines | contrast noticeably with visible lines |

dimensions | describe both size and location of features |

Arcs | Dimension by using the radius |

Circles | Dimension by using the diameter |

Circles | symbol precedes the circle size |

circles | Use a "X" when describing quantity |