6 Datums and Datum Systems
6.1 Datum Systems
6.1.1 Association of Datums
6.1.2 Datum: Mathematical Concepts
6.2 Indication of Datum Features in Technical Documentation
6.3 The Datum Systems in ASME Y14.5
6.3.1 Establishing a Datum
6.3.2 Location of a Workpiece in a Datum Reference Frame
6.3.3 Selection of Datum Features
6.4 Examples of Datum Systems in the ISO Standards
6.4.1 Datum System with Three Single Datums
6.5 Type of Datum
6.5.1 Centerplanes (Width-Type Features of Size)
6.5.2 Common Datum
6.5.3 Conical Surfaces as Datum Features
6.6 Datum Features Referenced at MMR and LMR (Size Datum)
6.7 Locked or Released Degrees of Freedom from a Datum
6.7.1 Customised Datum Reference Frame in the ASME Standards
6.8 Datum Targets
6.8.1 Contacting Feature
6.8.2 Datum Targets in the ASME Standards
