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Notes on Drawings

   You Still Need a Few Notes.

GD&T has greatly reduce the notes, in English, that are needed on the field of the drawing. There are still, however a few notes that may be required to suplement GD&T. I have often been asked to gather all of the notes found in ASME Y14.5M-1994 to provide a quick reference. The following is a table of the notes found in the Standard along with a brief explaination of their purpose and a reference to where you can learn more about their use. You might want to keep this tip close by as a handy reference.

Purpose of note:  Sample notes: ASME Y14.5M-1994 Reference:
For parts that are plated or coated, it is required that a note appears on the drawing stating when the dimensional limits apply. Examples: DIMENSIONAL LIMITS APPLY AFTER PLATING
DIMENSIONAL LIMITS APPLY BEFORE PLATING		 2.4.1
To override Rule #1 PERFECT FORM AT MMC NOT REQD 2.7.2
To establish a boundary of perfect form at MMC to control the relationship between features. PERFECT ORIENTATION (or COAXIALITY or LOCATION OF SYMMETRICAL FEATURES) AT MMC REQUIRED FOR RELATED FEATURES 2.7.3
To designate the specific feature of a thread, gear, spline, etc. which a geometric tolerance applies. MAJOR DIA
PITCH DIA
MINOR DIA		 2.10
Sample note that must appear on a drawing when the symbol is applied. FEATURES IDENTIFIED AS STATISTICALLY TOLERANCED SHALL BE PRODUCED WITH STATISTICAL PROCESS CONTROLS, (OR TO THE MORE RESTRICTIVE ARITHEMETIC LIMITS) 2.16.2
When it is necessary to relate linear and angular dimensions to a datum reference framework. This is not a substitute for datum references in a feature control frame. UNLESS OTHERWISE SPECIFIED, DIMENSIONS ARE RELATED TO DATUM A (PRIMARY), DATUM B (SECONDARY), AND DATUM C (TERTIARY) 4.4
To override simultaneous requirements. SEP REQT 4.5.12, 5.3.6.2
To override a separate requirements note or to invoke simultaneous requirements for the lower segment of multiple composite feature control frames. SIM REQT 4.5.12.1
To avoid having to apply the basic dimension symbol to each basic dimension. DIMENSIONS LOCATING TRUE POSITION ARE BASIC 5.2.1.1
Placed beneath a feature control frame to invoke the Boundary concept. BOUNDARY 5.10.1, 6.5.5.1
To indicate that a feature control frame applies to multiple holes shown on a common axis. TWO COAXIAL HOLES 5.11.1.6
To avoid having to apply the basic dimension symbol to each basic dimension. UNTOLERANCED DIMENSIONS ARE BASIC. Fig. 6-12
Placed below a feature control frame to indicate that the profile of a surface control applies to the entire part. ALL OVER 6.5.2
To control only an individual line element of a surface. EACH ELEMENT or EACH RADIAL ELEMENT 6.6.1.1
Used on repetitive patterns to reduce the number of different datums identified. INDIVIDUALLY 5.7
To specify where a tolerance applies. This permits closer control of a feature at one surface. AT SURF D 5.8

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