Canvas and Sectional Notes: Providing Specific Features

Notes on the technical drawings contain special conventions and symbols used on the drawing.

This information is provided to ensure that the reader correctly interprets the drawing. Notes are separated into two categories: (i)Sectional Notes, specified either directly on the sheet or near the views, and (ii)Canvas Notes, which are accompanied by a leader pointing to the specific features of the component.

Ignoring the Notes may lead to a lack of understanding of the technical drawing.

Canvas Notes

Canvas notes are commonly referred to as "General Notes." Certain numbers are written in the empty spaces outside the title block on the drawing sheet. Typically, the header is designated as "NOTES." These general notes placed outside the title block typically include the following:

  • A reference to standards used on the drawing. Don’t forget that some companies list a variety of applicable standards.

  • Machining processes that are used to the complete part. (e.g., the removal of all sharp edges.)

  • Common dimensions used throughout the drawing. (e.g., rounds of the same radius.)

  • Other details that relate to the whole drawing. (e.g., common surface finish or other treatments.)

 

Sectional Notes

Sectional notes are indicated close to the views on the drawing which referred to as "Specific Notes." These notes contain information regarding a specific section of the drawing part. (e.g., the internal feature details; the part number.)

 

The following is an example of a technical drawing with Canvas and Sectional notes:

Werk24 Explains Canvas and Sectional Notes in Technical Drawings
 

In the Notes section, specifications usually refer to industry-standard applications such as ASME and ANSI. Details in these and other nationally/internationally accepted standards can be used as a point of reference in general notes. So there may be some changes.

For example, Notes are printed on the drawing using uppercase text and read from the bottom of the sheet according to ASME standards. In Military standards, general notes place in the upper-left corner of the drawing.