From Geometrical Dimensioning and Tolerancing for Design, Manufacturing and Inspection: A Handbook for Geometrical Product Specification using ISO and ASME Standards, Second Edition
3.1 Symbols
The symbols for the drawing indications of geometrical tolerances according to ISO 1101, ISO 5459, ISO 286 and ISO 10579 are shown in Tables 3.1 and 3.2.
| Symbol | Interpretation |
|---|---|
|
 | |
|
 | |
| | Envelope requirement |
| | Maximum material requirement |
| | Least material requirement |
| | Reciprocity requirement |
| | Projected tolerance zone |
| | Flexible part in free state |
| | Regardless of feature size (ASME Y14.5) |
| | Tangent method (ASME Y14.5) |
| | Unsymmetrical tolerance zone (ASME Y14.8) |
| MD | Applies to major diameter of threads, splines, gears |
| PD | Applies to pitch diameter of threads, splines, gears |
| LD | Applies to (least) minor diameter of threads, splines, gears |
| LE | Applies to line elements (section lines) |
| NC | Not convex |
| ACS | Any cross-section |
| Further symbols are planned according to ISO 14 405 (in preparation) |
|
 |
Table 3.2 shows the symbols for the geometrical tolerance characteristics.
With the symbols of the left column of Table 3.2 all kinds of geometrical tolerances can be expressed. The symbols of the right column cover special cases that occur very frequently. These symbols are standardized in addition, and should be used in order to facilitate readability of drawings.
The proportions of the symbols for the drawing indications are standardized in ISO 7083. However, some CAD systems deviate from this standard. This may be tolerable as long as the drawing indications are unambiguous (as demonstrated in this book).
3.2 Definitions of geometrical tolerances
In order to specify geometrical tolerances, the workpiece is considered to be composed of features (geometrical...
Products & Services
A spline shafts has grooves or tongues machined along its length for torque transmission or anti-rotation linear guide applications.
Shoulder screws, also called stripper bolts, are a type of machine screw with integral threads that are only present on half or less of the screw shank. A shoulder screw has a partially smooth shaft that will allow the bolted material some rotation and movement around the screw axis, while the threaded end will typically have a nut to maintain the screw's position.
Topics of Interest
Profile tolerances are defined in ISO 1101, and profile tolerancing is described in ISO 1660. With profile tolerancing a distinction must be made between tolerancing of the form of lines (symbol and...
21.1 ASME Y14.5M 1994, ANSI B89.3.1 In the following the terminology of ASME Y14.5 is used (see Table 21.3). 21.1.1 Symbols The National Standard of the United States of America ASME Y14.5M-1994...
ISO 286-1 ISO System of limits and fits: bases of tolerances, deviations and fits ISO 1101 Geometrical tolerancing ISO 1660 Dimensioning and tolerancing of profiles ISO 2768-2 General...
Chapter List Chapter 1: Introduction Chapter 2: How to Use This Book Overview Engineering drawing practice (technical drawing) can be categorized into three sections: General principles This is...
Chapter List Chapter 3: Single Features Chapter 4: Symbols Chapter 5: Tolerance Frame Chapter 6: Datum Symbols Chapter 7: Datum Target Chapter 8: Toleranced Feature Chapter 9: Tolerance Zone...
