National and International Drawing Standards: Moving Toward Better Alignment with Y14.5

The task of revising the national standard on Dimensioning and Tolerancing, begun seven years ago, required close coordination between the Y14.5 Subcommittee and the U.S. expert members who participated in related activities of the International Organization for Standardization. The revised drawing standard about to be issued reflects additional international alignments in areas of metrication, symbology, and conventions. Differences remain in the prescribed symbol for indicating a datum feature and in a Principle of Independency, the latter unacceptably absolving size limits from controlling the geometric form of an individual feature. More U.S. member experts will be needed on the Y14.5 Subcommittee to uphold US viewpoints in the writing of international drawing standards of a pragmatic kind.