Geometric tolerancing is a method used in manufacturing to provide more precise control over a component's geometric features than basic dimensioning and tolerancing. It uses standardized symbols to specify geometric requirements for features and considers their form, orientation, location, and runout relative to datums. Only geometric tolerancing should be used if normal dimensioning is insufficient for a component's required design function. The symbols represent a range of potential geometric features and are constructed within tolerance frames that may or may not reference a datum depending on the geometric feature.

1. Geometric Tolerancing Design for Manufacture Geometric tolerancing Agreed by ISO 1001 included in BS308 (drawing standard) Author: Leicester College Date created: Date revised: 2009 Abstract: Geometric tolerancing is a method which is widely used in industry when the more basic systems of tolerancing component features does not provide the required accuracy. The system of geometric tolerancing id detailed together with the particular features of the system. © Leicester College 2009. This work is licensed under a Creative Commons Attribution 2.0 License.

2. These files support the Edexcel HN unit – Design for Manufacture (NQF L4) For further information regarding unit outcomes go to Edexcel.org.uk/ HN/ Engineering / Specifications Geometric Tolerancing

4. Symbols universally understood

7. Orientation

8. Location

10. Geometric Tolerancing Tolerance frame This type of frame used when no datum is required This type of frame used when a datum is specified – mandatory for some geometric features