0010// Reference Dimensions

Reference dimension is a useful tool for designer to deliver non-specification information to the reader of the drawing.

However, in production floor, reference dimension very often misuse as a product specification for inspector to fault the suppliers. Therefore, in this post, we will discuss what is reference dimension and its application.

Diagram below shown the key words, symbology and applcation of reference dimension, based on Y14.5-2009.

Definition (1.3.24)

Reference dimension is a dimension, usually without a tolerance, that is use for informational purposes only.

Symbology (3.3.8)

Two ways:

1) Indicated by enclosing dimension or other dimension data within parentheses.

2) Define dimension or other dimension data as reference in a note, the term "REFERENCE" or "REF" shall be used.

Examples of application

Example 1:

Overall dimension (1.7.7)

Example 2:

Ease of drawing interpretation (2.2.1.1)

Example 3:

Repeated dimension derived from other value shown in drawing (1.3.24)

Special note for basic dimension application:

Where basic dimension and datum feature symbol repeated on a drawing, it need not be indentified as reference. (1.3.24 & 3.3.2)

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