An upright T on a base line, specifying squareness to a datum.
Also known as: Squareness, Upside-down T drawing
The perpendicularity symbol requires a feature to be square to a datum. Unlike flatness it is meaningless without one — being perpendicular is a relationship, not a property.
Requires a feature to be square to a stated datum within the given tolerance.
Contexts: Technical drawing
Requires a datum reference, because perpendicularity is a relationship between two things rather than a property of one.
Contexts: Technical drawing
A vertical stroke rising from the centre of a horizontal base line, forming an inverted T inside the tolerance frame.
Geometric characteristic symbols.
The same figure as the mathematical perpendicularity relation.