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Geometrical Boundaries II , Interpretation and Application ISO - 2012

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Open: Geometrical Boundaries II, Interpretation and Application of G&T per. ISO 1101-2012

Written and Illustrated by Kelly L. Bramble

Geometrical Tolerancing is an engineering drawing language used to communicate the physical limit Requirements of a product object in two or three dimensional space. The G&T standard defines a collection of symbols and specific rules for defining specific characteristics, relationships, and feature controls.

The latest international standard on the subject of G&T defined and in practice is the International Standards Organization ISO 1101:2012, Geometrical Product Specifications (GPS).

Geometrical product specifications (GPS) — Geometrical tolerancing — Tolerances of form, orientation, location and run-out.

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 1101 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product specifications and verification.

This third edition cancels and replaces the second edition (ISO 1101:2004) and ISO 10578:1992. Representations of specifications in the form of a 3D model have been added.

1.2 Preface

1.3 Acknowledgments

1.4 Table of Contents

1.9 Introduction

1.10 Engineering Drawing Standards First and Third Angle Projection

1.11 Standards Based on ISO or ASME

1.16 Corporate Standards

1.17 Abbreviations

1.18 ISO Geometrical Symbols Text Equivalents

1.19 How the Geometrical Dimensioning and Tolerancing System Works

1.20 Geometrical Tolerances Symbols Overview

1.21 Tolerance Hierarchy

1.23 Tolerance Frame

1.24 Tolerance Frame Association and Application

1.25 Common Symbols ISO 1101:2012

1.26 Position and Limit Tolerance General Overview and Contrast

1.28 Recommended Fundamental Rules

Chapter 2

2.1 Limit Tolerancing

2.2 Dimensioning System –Limit


2.3 Implied 90 Degree Angle

2.3 Dimensional Expression

2.4 Dimension From … To

2.5 Gears, Splines and Screw Threads

2.6 Feature Definition – Size & Without Size

2.7 Materials Requirements, MMR, LMR

2.8 Principal of Independency

2.9 Envelope Requirement

Chapter 3

3.1 Datum coordinate system (DCS) overview

3.2 Immobilization of Component and Measurement

3.3 Datum Features and Datum Target Symbols

3.5 Datum identification

3.11 Datum Identification Features with Size Alternative and Special Applications

3.12 Datum associated with Tolerance Frame

3.13 Simulated datum, and Theoretical Datum Plane

3.14 Primary External Datum Diameter

3.15 Primary Internal Datum Diameter

3.16 Primary External Datum Width

3.17 Primary Internal Datum Width

3.18 Primary Datum Features Reference Chart

3.19 Setup and Inspection of Datum's

3.21 Sequence of datum features

3.22 Sequence of datum features relates part to datum coordinate system

3.24 Parts with angular orientation

3.26 Cylindrical datum feature

3.27 Orientation of Two Datum Planes Through a Hole

3.29 Partial Datum Surfaces as Datum Features

3.30 Multiple Datum features, Single Datum

3.31 Planar Multiple Datum Features Offset

3.26 Contoured Datum Feature Constraining a Rotational Degree of Freedom

3.27 Planar Datum Feature Constraining a Rotational Degree of Freedom

3.28 Inclined Datum Features

Chapter 4

4.1 Datum Targets Overview

4.2 Datum features and Datum Target Symbols

4.3 Datum Target Point Symbol, Application

4.4 Datum Target Area

4.5 Datum Target Line

4.6 Dimensioning Datum Targets

4.7 Primary Datum Plane Established by Three Datum Target Areas

4.8 Primary Datum Plane Established by Two Datum Target Points and One Datum Target Line.

4.9 Datum Targets Complex Surfaces Area

4.10 Datum Target Lines and Areas

4.11 Primary Datum Axis Established by Datum Target points on a Single Cylindrical Feature

4.12 Movable Datum

4.13 Secondary Datum Axis

4.17 Movable Datums Design Example

4.22 Datum Target Design Examples

Chapter 5

5.1 Form Tolerances General

5.2 Flatness

5.4 Flatness Applied to Multiple Unique Surfaces With the Same Value

5.5 Flatness Applied to Multiple Unique Surfaces as a Common Tolerance Zone

5.7 Flatness Applied on a Unit Basis

5.6 Flatness Applied on Unit Basis with Overall Control

5.9 Straightness

5.10 Straightness of a Surface (Cylindrical)

5.11 Straightness of a Feature of Size at RFS

5.12 Straightness of a Feature of Size at MMR

5.13 Straightness Per Unit Length With Specified Total Straightness

5.25 Cylindricity

5.27 Roundness

5.31 Roundness of Sphere

Chapter 6

6.1 Orientation Tolerances General

6.2 Perpendicularity – Surface

6.3 Perpendicularity Surface Multiple Datum's

6.15 Parallelism

6.16 Parallelism Control of Two Hole Features

6.17 Parallelism Hole Relative to Plane

6.18 Parallelism Hole Relative to Plane 2D vs 3D

6.26 Angularity

6.27 Angularity – Surface to Surface Datum With Location Control

6.28 Angularity – Hole and Planar Datum

6.29 Angularity – Hole and Datum Axis 2D and 3D

6.32 Angularity Tolerance of a Line Related to a Datum Plane 2D and 3D

6.34 Angularity Tolerance of a Surface Related to a Datum Plane 2D and 3D

Chapter 7

7.1 Tolerances of Location - General

7.2 Fundamental Explanation of Positional Tolerancing Feature of Size

7.4 Definitions and Modifiers

7.5 Maximum Material Requirement MMR

7.6 Least Material Requirement LMR

7.7 External Feature of Size Position Tolerance Boundaries with MMR Specification

7.8 Internal Feature of Size Position Tolerance Boundaries with MMR Specification

7.9 External Feature of Size Position Tolerance Boundaries with LMR Specification

7.10 Internal Feature of Size Position Tolerance Boundaries with LMR Specification

7.11 Zero positional tolerance at MMR

7.12 Position Tolerance at RFS

7.13 Positional Tolerance Axis and Surface Interpretation – Surface Datum's

7.16 Positional Tolerance Axis and Surface Interpretation - Thru Hole Datum's

7.19 Positional Tolerance of a Cylinder 2D and 3D

7.21 Positional Tolerance of a Line 2D and 3D

7.24 Positional Tolerance at MMR Relative to Hole and Slot Datum Feature

7.25 Position Tolerance Applied to a Flat Surface

7.28 Bidirectional Positional Tolerancing, Polar Coordinate Method

7.31 Coaxial (Concentric) Control of Multiple Hole-Counterbore Holes

7.33 Hole Pattern Located Perpendicular to Cylindrical Datum

7.34 Hole Pattern Located Perpendicular to Cylindrical Datum

7.35 Hole Pattern Located at Angle to Datum Reference Frame

7.36 Positional Tolerance at MMR of Spherical Feature (Point)

7.39 Positional Tolerance of Coaxial Holes of Same Size

7.43 Positional Tolerance - Thru Hole Datum's at MMR

7.45 Composite Positional Tolerancing

7.51 Coaxiality Tolerancing of an Axis

7.54 Concentricity of a Point Tolerance

7.56 Symmetry Tolerance of a Median Plane

7.57 Symmetry Tolerance of a Median Plane

Chapter 8

8.1 Profile General

8.2 Profile Surface Definition

8.3 Profile any Surface, Bilateral Tolerance

8.4 Profile any Surface, Bilateral Tolerance 2D vs 3D

8.5 Profile any Surface, Bilateral Tolerance Rectangular Coordinate Dimensioning Without Dimension Lines

8.7 Alternative Practice Unequally Disposed Tolerance Zone

8.9 Profile any Surface, Unilateral (OUTSIDE) Tolerance

8.10 Alternative Practice Unilateral (OUTSIDE) Disposed Tolerance Zone

8.12 Profile any Surface, Bilateral Unequal Tolerance

8.14 Profile any Surface, All Around

8.17 Profile any Surface Tolerance Independent Form Control Not related to Datum

8.18 Profile Tolerance for Coplanar Surfaces and Common Zone

8.19 Profile any Line

8.20 Profile any Line 2D vs 3D

8.22 Profile any Line Without Datum Reference

8.25 Profile any Line Tapered Shape

8.27 Composite Profile Tolerance

Chapter 9

9.1 Run-out General

9.2 Circular Run-out

9.4 Circular Run-out Tolerance Partial Cylinder

9.4 Circular Run-out, Perpendicular Surface

9.5 Total Run-out

9.6 Circular Run-out, Tapered Surface

9.7 Circular Run-out, Tapered Surface in a Specified Direction

9.8 Circular Run-out, Tapered Surface

9.9 Circular Run-out, Perpendicular Surface Axial

9.11 Total Run-out

9.15 Run-Out With Plane as Datum

9.18 Run-Out With Two Datum Diameters

Chapter 10

10.1 Coaxial Tolerance Comparison

Chapter 11

11.1 Tolerance Conversion Unilateral - Bilateral

11.2 Series Stack Calculations

11.3 Floating Fastener Condition

11.4 Fixed Fastener Condition

11.5 Tolerance Compensation for Projected Tolerance Zone – Fixed Fastener condition

11.7 Two Mating Diameters Positional Calculation

11.8 Three Mating Diameters Positional Calculation

11.9 Position Tolerance Verification and Hole Pattern Analysis

11.11 Position Coordinate to Location Conversion Chart

11.12 Generic Hole Verification Chart

Chapter 12

12.1 Critical Feature Drawing

(Reduced Dimension Drawing)

12.2 Implementation Considerations Applicable Documents, Overview

12.3 Design Drawing Requirements Digital Model and Database

12.4 Quality and Inspection Requirements Manufacturing

12.5 Change Notice Procedure

Chapter 13

13.1 Comparison of ISO and ASME Symbols

Chapter 14

14.1 Glossary and Definitions

Appendix A

15.1 ANSI Standard Size (Inch) Drills

15.3 ISO Metric (mm) Size Standard Drill Sizes

15.4 ANSI External Screw Threads Sizes 0 - 3/8

15.5 ANSI External Screw Threads Sizes 3/8 – Larger

15.6 ACME Thread Forms – General Purpose External

15.7 ACME Thread Forms – General Purpose Internal

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