Foreword
Introduction
Scope
Normative references
Terms and definitions
Symbols
Role of datums
General concepts
General
Intrinsic characteristics of surfaces associated with datum features
General
Single datum established from a single feature
Common datum established from two or more single features simultaneously
Datum systems established in a defined sequence from two or more single features
Single datums, common datums and datum systems
General
Single datums
Common datums
Datum systems
Graphical language
General
Indication of datum features
Datum feature indicator
Datum feature identifier
Datum targets
General
Datum target frame
Datum target symbol
Leader line
Specification of datums and datum systems
Indication and meaning of rules
General
Rules
Rule 1 — Datum features (established from a single feature)
Rule 2 — Size status for associated features of size
General
Associated feature of size with variable size
General
Rule 2A — Implicit definition of variable size
Rule 2B — Explicit indication of variable size
Associated feature of size with fixed size
General
Rule 2C — Implicit definition of fixed size
Rule 2D — Explicit indication of fixed size
Rule 3 — Datum features established from a complete feature
Rule 4 — Datum features established from one or more datum targets
Rule 5 — Associated feature with a different type than the nominal datum feature
Rule 6 — Tolerance frame layout with a datum or a datum system
Rule 7 — Indication of a single or common datum in a datum indicator of a datum section
Rule 8 — Locked or released degrees of freedom from a datum
Rule 9 — Special indications for common datum
Rule 10 — Application of geometrical modifiers in a tolerance frame
Rule 11 — Indirect indication of a datum section
Rule 12 — Indication of a situation feature
Specification operators for datum
ISO default specification operator for datum
Special specification operator for datum
General
Filtration specification elements for datum
Association specification elements for datum
Drawing-default specification operator for datums
Association for datums (normative)
Basic concepts
Association methods
General
Association for single datums
Association for single datums without the [CF] modifier
Association for single datums with the modifier [CF]
Default association criteria
Association for common datums
General
Default association criteria
Association for datum systems
General
Default association criteria
Invariance classes (informative)
Examples (informative)
General
Examples of single datums
Plane
Cylinder
Cone
Sphere
Particular situation feature
Obvious situation feature
Only one situation feature needed
Complex surface
Intersecting planes
Two parallel opposite planes (defined as a feature of size)
Three datum targets on a plane
Examples of common datums
Two coplanar planes
Two coaxial cylinders
Plane and cylinder perpendicular to each other
Two parallel cylinders
Pattern of five cylinders
Two parallel planes
Examples of datum systems
Three perpendicular planes
Cylinder and perpendicular plane
Former practices (informative)
Indication of a specific cross-section of a cylinder as a datum feature
Datum target line indication
Common datum indication
CE, GE and new filter for a planar single datum case
Examples of a datum system or a common datum established with contacting features (informative)
Example 1
Example 2
Example 3
Example 4
Example 5 — Example for a “three jaw chuck”
Relations and dimensions of graphical symbols (normative)
Establishment of a datum coordinate system from a datum system (normative)
General
Indication of a datum coordinate system
Datum coordinate system indicator
Datum coordinate system identifier
Filter symbols and attached nesting index (informative)
Issue of orientation and location constraints in datum systems (informative)
Construction of associated feature for defining a datum system
Example 1
Example 2
Example 3
Filtration of a datum feature which is nominally a plane (normative)
General
Filtration
General
Mathematical concepts and symbols
Examples
Relation to the GPS matrix model (informative)
General
Information about the document and its use
Position in the GPS matrix model
Related International Standards
Bibliography