Question
When revising drawings to include the delta triangle in the title block, does the drawing index sheet also contain the triangle in the title block?
Answer
The term “delta” refers to a triangle placed on the drawing for reference. The triangle is commonly placed next to a dimension, such as 2.65, 5, or other locations where it applies to a feature or item. This is used to refer the reader to a general note that relates to this item.
So if the delta triangle is used as a reference in your main title block, then I would say yes, add it to the index sheet if it makes the reference more clear.
In addition to drawing a reader’s attention to notes, the delta triangle is also quite often used with print revisions. For example, if a drawing was a revision 2, and then a new revision is generated. It might say something simple like, Rev. 3- 2.235 dimension changed to 2.240. Then a delta triangle with the number 3 in it would be next to the 2.240 dimension referring to the revision.
Bud Salsbury
ASQ Senior Member, CQT, CQI