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NASA Engineering Drawing Standards Manual

Drafting, Design and Engineering Drawings

Engineering Drawing Standards Manual
NASA
Mechanical Engineering Branch
Goddard Space Flight Center

Open: Engineering Drawing Standards Manual
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Introduction

This drawing standards manual establishes the conventions to be adhered to by engineering and drafting personnel in the preparation, revision, and completion of engineering drawings. This manual sets forth the minimum requirements acceptable at GSFC for the preparation of engineering drawings for flight hardware and ground support systems. The requirements specified herein are essential to the standardization of practices and to a uniform interpretation of drawings.

A system, payload, or component assembly shall be completely defined by means of drawings, including lists, schematics, wiring diagrams, and specifications, to ensure that components fabricated are in accordance with the design. The documentation information shall serve as a permanent record.

Flight hardware shall be fabricated in accordance with the approved design documents. These documents shall reflect the characteristics and acceptance criteria for all materials, component/parts, subsystems, and the complete system. The acceptance criteria for parts and materials shall be specified by standard specifications when applicable.

Engineering drawings are defined as those drawings that communicate the requirements for the manufacture of the end-product items, their assembly, and their installation in the end product.

The engineering drawings prepared by GSFC design personnel or contractors on GSFC drawing format using GSFC drawing numbers shall be known as “Government Design Activity Drawings.” Parts made to these drawings typically would be manufactured through the Fabrication Engineering Branch, Engineering Services Division, GSFC.“Contractor Design Activity Drawings”””” (which are a company's drawings bearing the company name, address, federal code identification, and drawing number) should be used when the company is designing and delivering the finished product in accordance with the terms of a NASA contract.

The Design Activity shall be defined as an activity having responsibility for the design of an item or system. The activity may be a government entity, a contractor, a vendor, or another organization such as a university.

Although generally in accordance with the Department of Defense and industry practices and procedures, this drawing standards manual does contain specific differences and exceptions to Engineering Drawing Practices, MIL-STD-100E. This manual, while not intended as a manual of instruction in the basic principles of drafting, does set forth the minimum requirements acceptable at the GSFC. One of those requirements is that persons engaged in the preparation of drawings shall have a thorough understanding of the fundamentals of drafting and geometrical dimensioning and tolerancing (in accordance with ANSI Y14.5M-1982, Dimensioning and Tolerancing) in order to produce interpretable drawings.

TOC

INTRODUCTION ....................................................................................................... 1
1. DRAWING ELEMENTS .......................................................................................... 3
1.1. Drawing Sizes ................................................................................................. 3
1.2. Multisheet Drawings ........................................................................................ 3
1.3. Zoning ............................................................................................................ 4
1.4. Title Block and Revision Block ......................................................................... 4
1.5. Drawing Format .............................................................................................. 10

2. NOMENCLATURE ................................................................................................ 11
2.1. Drawing Title ................................................................................................. 11
2.2. Abbreviations ................................................................................................. 12
2.3. List of Material .............................................................................................. 14
2.3.1. Requirements on the Body of the Drawing ................................................ 14
2.3.2. Requirements in the List of Material ........................................................ 14
2.4. Notes on Drawings .......................................................................................... 15
2.4.1. Security Classification ........................................................................... 15
2.4.2. Note Location........................................................................................ 15
2.4.3. Numbering of Notes ............................................................................... 16
2.4.4. Note Examples ...................................................................................... 16
2.4.4.1. Dimension Notes ........................................................................ 16
2.4.4.2. Heat Treating Notes.................................................................... 17
2.4.4.3. Joining Method Notes (welding, brazing, etc.) ............................... 18
2.4.4.4. Plating and Coating Notes ........................................................... 18
2.4.4.5. Surface Preparation Notes ........................................................... 19
2.4.4.6. Testing and Inspection Notes ....................................................... 20
2.4.4.7. Threaded Inserts — Cleaning and Installation Notes ....................... 20
2.4.4.8. Miscellaneous Notes ................................................................... 21
2.4.4.9. Informational Notes .................................................................... 23
2.4.5. Local Character Notes ............................................................................ 23
2.4.6. General Dimensional Tolerance Notes ...................................................... 23
2.5. Specification Callouts ..................................................................................... 23

3. DRAFTING PRACTICES ....................................................................................... 25
3.1. General .......................................................................................................... 25
3.2. Lines ............................................................................................................. 25
3.2.1. Ink Lines and Plotted Lines .................................................................... 25
3.2.2. Pencil Lines .......................................................................................... 27
3.2.3. Types of Lines....................................................................................... 27
3.2.3.1. Center Lines .............................................................................. 27
3.2.3.2. Dimension Lines ........................................................................ 28
3.2.3.3. Leaders ..................................................................................... 28
3.2.3.4. Break Lines ............................................................................... 28
3.2.3.5. Phantom Lines ........................................................................... 29
3.2.3.6. Sectioning Lines ........................................................................ 29
3.2.3.7. Extension Lines ......................................................................... 30
3.2.3.8. Hidden Lines ............................................................................. 30
3.2.3.9. Stitch Lines ............................................................................... 30
3.2.3.10. Outlines or Visible Lines........................................................... 30
3.2.3.11. Datum Lines ............................................................................ 30
3.2.3.12. Cutting-Plane/Viewing-Plane Lines ............................................ 30
3.3. Lettering and Numerals ................................................................................... 31
3.3.1. Style .................................................................................................... 31
3.3.2. Heights ................................................................................................. 32
3.4. Scale ............................................................................................................. 32
3.5. Positioning the Part on the Drawing .................................................................. 33
3.5.1. Picturization ......................................................................................... 33
3.5.2. Sections ................................................................................................ 34
3.5.3. Views ................................................................................................... 36
3.5.4. Details .................................................................................................. 37
3.5.5. Identification of Sections, Views, and Details ........................................... 37
3.5.6. Locating Sections, Views, and Details ...................................................... 38

4. TYPES OF DRAWINGS ......................................................................................... 39
4.1. Altered or Selected Vendor Part Drawing .......................................................... 39
4.2. Assembly Drawing .......................................................................................... 40
4.3. Detail Drawing ............................................................................................... 41
4.4. Drawing Tree ................................................................................................. 42
4.5. Electrical/Electronic Drawings ......................................................................... 43
4.5.1. Electrical and Electronic Symbols............................................................ 43
4.5.2. Electrical and Electronic Diagrams .......................................................... 43
4.6. Inseparable Assembly Drawing ......................................................................... 44
4.7. Installation Assembly Drawing ......................................................................... 45
4.8. Interface Control Drawing ............................................................................... 46
4.9. Matched-Set Drawing ...................................................................................... 48
4.10. Mechanical Schematic .................................................................................... 49
4.11. Modification Drawing .................................................................................... 51
4.12. Outline Drawing ........................................................................................... 51
4.13. Source Control Drawing ................................................................................. 53
4.14. Specification Control Drawing ........................................................................ 54
4.15. Standard Part Drawing ................................................................................... 56
4.16. Tabulated Drawing ........................................................................................ 56
4.17. Tooling Drawing ........................................................................................... 57
4.18. Composite Material Drawing .......................................................................... 58

5. NUMBERING SYSTEM FOR DRAWINGS AND SUPPORTING DOCUMENTATION . 60
5.1. Part Numbering .............................................................................................. 61
5.2. Find or Item Numbering................................................................................... 62
5.3. Order of Precedence of Specifications and Standards .......................................... 62
5.3.1. Group I ................................................................................................. 62
5.3.2. Group II ............................................................................................... 62
5.3.3. Group III .............................................................................................. 63
5.3.4. Group IV .............................................................................................. 63
5.3.5. Group V................................................................................................ 63
6. ENGINEERING ORDER ........................................................................................ 64
6.1. General Requirements...................................................................................... 64
6.2. Format Sample ................................................................................................ 64
7. DRAWING REVISIONS ......................................................................................... 68
7.1. Revision Methods ........................................................................................... 68
7.2. Revision Identification .................................................................................... 68
7.3. Revision of Multisheet Drawings ...................................................................... 68
7.4. Revision Recording ......................................................................................... 68
7.5. Redrawn or Replaced Drawings ........................................................................ 70

8. PARTS LIST AND INDEX LIST ............................................................................. 71
8.1. Definitions ..................................................................................................... 71
8.2. Requirements.................................................................................................. 71
8.2.1. List Preparation ..................................................................................... 71
8.2.2. List Formats .......................................................................................... 72
8.2.3. Revision Identification ........................................................................... 72
8.2.4. Deleting Items ....................................................................................... 72
8.2.5. Adding Items ......................................................................................... 72
8.3. Cover Sheet.................................................................................................... 72
8.3.1. Format .................................................................................................. 72
8.3.2. Entries.................................................................................................. 72
8.4. Parts List Continuation Sheet ........................................................................... 75
8.4.1. Format .................................................................................................. 75
8.4.2. Entries.................................................................................................. 75
8.5. Index List Continuation Sheet .......................................................................... 77
8.5.1. Format .................................................................................................. 77
8.5.2. Entries.................................................................................................. 77
8.6. Find or Item Number System of Identification .................................................... 79
8.6.1. Definition ............................................................................................. 79
8.6.2. Application and Limitation ..................................................................... 79
8.6.3. Drawing Requirements ........................................................................... 80
8.7. List of Material .............................................................................................. 81
8.7.1. Format .................................................................................................. 81
8.7.2. Entries.................................................................................................. 81

9. DOCUMENTATION MANAGEMENT ..................................................................... 82
9.1. Typical Drawing Flow for Flight Projects .......................................................... 82
9.2. Archiving....................................................................................................... 83
9.3. Computer-Aided Design Drawings .................................................................... 83
9.3.1. Presentation of Computer-Generated Data ................................................. 83
9.3.2. Developing and Using Computer-Generated Drawings ................................ 84
9.3.3. Specification Data ................................................................................. 84

10. DESIGN REFERENCES, STANDARDS, AND SPECIFICATIONS ........................... 85
10.1. Dimensioning and Tolerancing ........................................................................ 85
10.1.1. Dimensioning and Tolerancing Practices ................................................. 85
10.1.2. Statements on Dimensioning .................................................................. 85
10.2. Metric Dimensioning ..................................................................................... 86
10.2.1. SI Units and Symbols ........................................................................... 86
10.2.2. Unit Conversions ................................................................................. 89
10.2.2.1. Conversion of Dimensions ......................................................... 89
10.2.2.2. Unit Rounding.......................................................................... 89
10.3. Design References ......................................................................................... 92
10.4. Control of Surface Roughness ......................................................................... 93
10.4.1. Surface Texture ................................................................................... 93
10.4.2. Surface Texture Symbols ...................................................................... 93
10.4.3. Surface Texture Standards ..................................................................... 93
10.5. Thread Specifications .................................................................................... 93
10.6. Welding—Fusion and Resistance ..................................................................... 95
10.6.1. General ............................................................................................... 95
10.6.2. Basic Weld Symbols and Their Location Significance .............................. 95
10.7. Outgassing of Spacecraft Materials ................................................................. 95
10.8. Standards and Specifications Index ................................................................. 96
10.8.1. National Bureau of Standards ................................................................ 96
10.8.2. Federal ............................................................................................... 96
10.8.3. Industrial ............................................................................................ 97
10.8.4. Military .............................................................................................. 98
10.8.5. NASA ............................................................................................... 100
10.9. Standards and Specifications Numerical Index ................................................ 101

APPENDIX A. DESIGN REVIEW DOs AND DON'Ts................................................ 107
INDEX.................................................................................................................... 110