BS 3643-1:2007:2009 Edition
$215.11
ISO metric screw threads – Principles and basic data
| Published By | Publication Date | Number of Pages |
| BSI | 2009 | 76 |
This part of BS 3643 gives a compilation of principles and basic data for single-start, parallel screw threads having the ISO basic profile for triangular screw threads. Guidance on calculating limits of size for metric screw threads not included in Tables 1 to 14 is given in Annex B.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 3 | Contents 1 Scope 1 2 Normative references 1 3 Terms and definitions and symbols 1 4 Basic profile 2 5 General plan 5 6 Basic dimensions 8 7 Tolerances – Principles and basic data 18 8 Tolerances – Deviations for constructional threads 35 9 Tolerances – Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanizing 53 10 Tolerances – Limits of sizes for internal screw threads to mate with hot-dip galvanized external screw threads with maximum size of tolerance position h before galvanizing 55 Annexes Annex A (informative) Notes for guidance 60 Annex B (informative) Examples of calculations of limits of size for metric screw threads 65 Bibliography 68 List of figures Figure 1 – Basic profile of ISO metric thread 3 Figure 2 – Basic dimensions 8 Figure 3 – Tolerance positions with respect to zero line (basic size) 19 Figure 4 – Internal threads with tolerance position G 21 Figure 5 – Internal threads with tolerance position H 22 Figure 6 – External threads with tolerance positions e, f and g 22 Figure 7 – External threads with tolerance position h 23 Figure 8 – External root profile 31 Figure A.1 – Maximum material profiles for internal and external threads 61 Figure B.1 – Illustration of limits of size for external thread (see Example 1) 66 List of tables Table 1 – Basic profile dimensions 4 Table 2 – Maximum nominal diameter 5 Table 3 – Diameter/pitch combinations 6 Table 4 – Basic dimensions 9 Table 5 – Fundamental deviations for internal threads and external threads 24 Table 6 – Lengths of thread engagement 25 Table 7 – Minor diameter tolerances of internal threads (TD1) 26 Table 8 – Major diameter tolerances of external threads (Td) 27 Table 9 – Pitch diameter tolerances of internal threads (TD2) 28 Table 10 – Pitch diameter tolerances of external threads (Td2) 29 Table 11 – Minimum root radii 31 Table 12 – Recommended tolerance classes for internal threads 32 Table 13 – Recommended tolerance classes for external threads 32 Table 14 – Deviations 36 Table 15 – Deviations for hot-dip galvanized external threads 54 |
| 4 | Table 16 – External thread limits for tolerance class 6az 55 Table 17 – Deviations for internal threads to mate with hot-dip galvanized external threads 57 Table 18 – Internal screw thread limits for tolerance class 6AZ 58 Table 19 – Internal screw thread limits for tolerance class 6AX 59 Table A.1 – Nominal stress areas for external screw threads – Coarse series 63 Table A.2 – Nominal stress areas for external screw threads – Fine series 64 |
| 5 | Foreword |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions and symbols 3.1 Terms and definitions 3.1.1 basic profile |
| 8 | 3.2 Symbols 4 Basic profile 4.1 General 4.2 Dimensions |
| 9 | Figure 1 Basic profile of ISO metric thread |
| 10 | Table 1 Basic profile dimensions |
| 11 | 5 General plan 5.1 General 5.2 Designation 5.3 Choice of diameter and pitch Table 2 Maximum nominal diameter |
| 12 | Table 3 Diameter/pitch combinations |
| 13 | Table 3 Diameter/pitch combinations (continued) |
| 14 | 6 Basic dimensions 6.1 General 6.2 Basic dimensions Figure 2 Basic dimensions |
| 15 | Table 4 Basic dimensions |
| 16 | Table 4 Basic dimensions (continued) |
| 24 | 7 Tolerances – Principles and basic data 7.1 General 7.2 Structure of the tolerance system a) A series of tolerance grades for each of the four screw thread diameters, as follows: b) A series of tolerance positions: c) A selection of recommended combinations of grades and positions (tolerance classes) giving the commonly used tolerance qualit… |
| 25 | Figure 3 Tolerance positions with respect to zero line (basic size) 7.3 Designation |
| 27 | 7.4 Tolerance grades 7.5 Tolerance positions Figure 4 Internal threads with tolerance position G |
| 28 | Figure 5 Internal threads with tolerance position H Figure 6 External threads with tolerance positions e, f and g |
| 29 | Figure 7 External threads with tolerance position h |
| 30 | Table 5 Fundamental deviations for internal threads and external threads |
| 31 | 7.6 Lengths of thread engagement Table 6 Lengths of thread engagement |
| 32 | 7.7 Crest diameter tolerances 7.7.1 Minor diameter tolerances of internal threads (TD1) Table 7 Minor diameter tolerances of internal threads (TD1) |
| 33 | 7.7.2 Major diameter tolerances of external threads (Td) Table 8 Major diameter tolerances of external threads (Td) 7.8 Pitch diameter tolerances |
| 34 | Table 9 Pitch diameter tolerances of internal threads (TD2) |
| 35 | Table 10 Pitch diameter tolerances of external threads (Td2) |
| 36 | 7.9 Root contours |
| 37 | Figure 8 External root profile Table 11 Minimum root radii |
| 38 | 7.10 Recommended tolerance classes Table 12 Recommended tolerance classes for internal threads Table 13 Recommended tolerance classes for external threads |
| 39 | 7.11 Formulae 7.11.1 General 7.11.2 Fundamental deviations 7.11.3 Length of thread engagement |
| 40 | 7.11.4 Crest diameter tolerances 7.11.4.1 Tolerances for major diameter of external threads (Td), grade 6 7.11.4.2 Tolerances for minor diameter of internal threads (TD1), grade 6 a) Pitches 0.2 mm to 0.8 mm: b) Pitch 1 mm and coarser: 7.11.5 Pitch diameter tolerances 7.11.5.1 Tolerances for pitch diameter of external threads (Td2) |
| 41 | 7.11.5.2 Tolerances for pitch diameter of internal thread (TD2) 8 Tolerances – Deviations for constructional threads 8.1 General 8.2 Deviations |
| 42 | Table 14 Deviations |
| 43 | Table 14 Deviations (continued) |
| 59 | 9 Tolerances – Limits of sizes for hot-dip galvanized external screw threads to mate with internal screw threads tapped with tolerance position H or G after galvanizing 9.1 General 9.2 Designation |
| 60 | 9.3 Deviations Table 15 Deviations for hot-dip galvanized external threads 9.4 Limits of sizes – External screw threads – Coarse thread series |
| 61 | Table 16 External thread limits for tolerance class 6az 10 Tolerances – Limits of sizes for internal screw threads to mate with hot-dip galvanized external screw threads with maximum size of tolerance position h before galvanizing 10.1 General |
| 62 | 10.2 Designation 10.3 Deviations |
| 63 | Table 17 Deviations for internal threads to mate with hot-dip galvanized external threads |
| 64 | 10.4 Limits of sizes – Internal screw threads – Coarse thread series Table 18 Internal screw thread limits for tolerance class 6AZ |
| 65 | Table 19 Internal screw thread limits for tolerance class 6AX |
| 66 | Annex A (informative) Notes for guidance A.1 Maximum material profile A.2 Coatings A.3 External threads – Stress areas A.4 External threads – Minor diameters |
| 67 | Figure A.1 Maximum material profiles for internal and external threads |
| 68 | Figure A.1 Maximum material profiles for internal and external threads (continued) |
| 69 | Table A.1 Nominal stress areas for external screw threads – Coarse series |
| 70 | Table A.2 Nominal stress areas for external screw threads – Fine series |
| 71 | Annex B (informative) Examples of calculations of limits of size for metric screw threads |
| 72 | Figure B.1 Illustration of limits of size for external thread (see Example 1) |
| 74 | Bibliography |
