Geometric Dimensioning and Tolerancing

MIL-HBK-727

Feature Control Frame

Datums

Rule 1-Indivdual Feature of Size Where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent to which variations in geometric form, as well as size, are allowed. (ASTM Y ). Meaning?

10±1 5±1 11 6

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson Fundamentals of Graphics Communication – Bertoline and Weibe

Engineering Design Communication – Lockhart and Johnson

Fundamentals of Graphics Communication – Bertoline and Weibe

Summary  All dimensions include controls of geometry. Rule 1 states that a size control inherently includes controls of form.  Because of Rule 1, the need for GDT callouts is minimized. Use carefully.  GDT should be used to refine the relationship between feature and form.  GDT should open tolerances. MMC should reduce part cost. Technical Graphics Communication, Bertoline, et al