Geometric Dimensioning and Tolerancing

MIL-HBK-727

MIL-HBK-727

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 Y14.5-1994).

Meaning?

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

Fundamentals of Graphics Communication – Bertoline and Weibe

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