TS 1304 ISO 1101

TS 1304 ISO 1101 is a geometrical tolerancing standard for technical drawings, covering how form, orientation, location and run-out tolerances are symbolized and indicated. Its purpose is to help define not only the size of a part, but also the geometric behavior that must be achieved for the design intent to be met.

The role of geometrical tolerancing in drawings

Geometrical tolerancing gives design, manufacturing and inspection a common language. Dimensional values define the nominal size of a feature, while geometrical tolerances describe how flat, straight, round, aligned, positioned or rotating-related that feature may be within acceptable limits. This standard covers the general principles for showing those tolerances on drawings and the corresponding geometrical definitions.

Tolerance groups covered by the standard

• Form tolerances: limit the shape of a feature itself, such as flatness, straightness, circularity and cylindricity.
• Orientation tolerances: control the direction of a surface or axis relative to a reference.
• Location tolerances: define where a feature is placed in relation to other features.
• Run-out tolerances: restrict the variation associated with a rotating part or rotating surface.

In general engineering drawing practice, these distinctions matter because two parts with the same nominal dimensions may still perform differently if their geometric tolerances differ. TS 1304 ISO 1101 is one of the core references for making that communication systematic on the drawing. This listing is recorded as equivalent to the 1983 edition of the international standard, and the standard itself is withdrawn.