TS 2955

TS 2955 is the standard that addresses form and position tolerances in technical drawings in connection with the maximum material principle, and how that principle is applied. Its subject is the relationship between size tolerance and geometric tolerance, especially in the way assembly fit, hole-and-shaft features, and related functional elements are represented on drawings.

What the maximum material principle means

In general technical terms, the maximum material principle is based on the idea that a feature may receive additional geometric tolerance when it is at the limit containing the greatest amount of material. This helps the designer and manufacturer interpret form and position deviations in a way that preserves function when the actual size remains within the permitted size range. It is especially relevant for assembly conditions, fits, and locating features.

The standard covers the way this principle is expressed in technical drawing and how it is connected to form and position tolerances. In practice, that means the drawing does more than state a dimension: it also clarifies the link between geometric accuracy and functional assembly. This supports consistent dimensioning and tolerancing and provides a common language between design, production, and inspection.

• Form tolerances limit how much a feature may deviate from its ideal geometric shape.
• Position tolerances control the location of a feature or its axis relative to references.
• The maximum material principle allows size limits and geometric tolerance to be considered together.
• Its drawing notation helps define the functional mating of parts more clearly.