This Standard relates to screw threads of buttress form and provides: a) A form of 7 degrees\/45 degrees buttress thread with 0.6p basic height of thread engagement (see Fig. 1a); b) A table of preferred diameter-pitch combinations (see Table 1); c) A formula for calculating pitch diameter tolerances (see Para. 6.1); d) Tolerances for major and minor diameters (see Para. 6.2 and 6.3); e) A system of allowances between external and internal threads (see Para. 7); f) Recommended methods of measuring and gaging (see Para. 10 and 11); g) Dimensional acceptability of buttress product (see Section 12).<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 7<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | Section 1. Scope 2. Definitions 3. Form of Thread <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | FIGURES Fig. 1a Form of Standard 7’\/45′ Buttress Thread with 0.6p Basic Height of THread Engagement and Round Root Fig. 1b Form of 7’\/45′ Buttress Thread with 0.6p Basic Height of Thread Engagement and Flat Root <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 4. Symbols and Formulas <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 5. Preferred Diameter-Pitch Combinations 6. Tolerances 6.1 Pitch Diameter Tolerances TABLES Table 1 Diameter-Pitch Combinations for 7″\/45″ Buttress Threads <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | Table 2 Basic Dimensions for 7’\/45′ Buttress Threads of Preferred Pitches <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | Table 3 Tolerances, Class 2 (Standard Grade) Fig. 2 Disposition of Buttress Thread Tolerances, Allowances, and Root Trunctions <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 6.2 Tolerances on Major Diameter of External Thread and Minor Diameter of Internal Thread 6.3 Tolerances on Minor Diameter of External Thread and Major Diameter of Internal Thread 6.4 Lead and Flank Angle Deviations for Class 2 6.5 Diameter Equivalents for Variations in Lead and Flank Angles for Class 3 6.6 Tolerances on Taper and Roundness Table 4 Tolerances, Class 3 (Precision Grade) <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 7. Allowance for Easy Assembly 8. Example Showing Dimensions for a Typical Buttress Thread (2 Inch Diameter, 4 TPI, 7’\/45′ Flank Angles, Class 2) 9. Thread Designations 9.1 Thread Designation Abbreviations 9.2 Designations for Standard Threads <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 9.3 Superseded Designations 10. Measurement of Buttress Thread Gages and Product Table 5 Allowances, Classes 2 and 3 <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 10.1 Pitch Diameter Determination of Threaded Plug Gages 10.2 Pitch Diameter Determination of Threaded Ring Gages 10.3 Pitch Diameter Determination of External Product Threads 10.4 Pitch Diameter Determination of Internal Product Threads 10.5 Lead and Flank Angle Measurement 11. Recommended Gaging Practice 11.1 Recommended Gages and Gaging Practice for External Thread <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 11.2 Recommended Gages and Gaging Practice for Internal Thread <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | Table 6 X Gagemaker’s Tolerances for GO and NOT GO Buttress Threaded Plug, Ring, Snap and Indicating Gages <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | Table 7 W Gagemaker’s Tolerances for GO and NOT GO Buttress Threaded Setting Plug Gager <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 11.3 Root Relief Width for Gages 11.4 Gage Tolerances 12. Dimensional Acceptability of Buttress Product Screw Threads 12.1 Dimensional Acceptability of Class 2 Buttress Product Threads 12.2 Dimensional Acceptability of Class 3 Buttress Product Threads Table 8 Gagemaker\u2019s Tolerances for Plain Plug, Ring and Snap Gages <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | Table 9 Pitch Diameter Equivalents for Lead Deviations <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | Table 10 Pitch Diameter Equivalents for Flank Angle Deviations <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | Appendix A – Pitch Diameter Equivalents for Lead and Flank Angle Deviations A.1 Lead Deviations A.2 Flank Angle Deviations A.3 Computed Functional Size <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Appendix B – Pitch Diameter Measurement B.1 Measurement of Pitch Diameter of External Buttress Threads B.2 Measurement of Pitch Diameter and Groove Diameter of Internal Buttress Threads <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | Table 11 Thread-Measuring Wires for 7\u2019\/45\u2019 Buttress Threads <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | B.3 Lead-Angle Correction Fig. 3 Measuring Steps for Internal Pitch Diamater <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | B.4 Wire SIzes Fig. 4 Diameters of “Best” and “Maximum” Thread Wires for Buttress Screw Threads <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | Appendix C – Notes on Corresponding British Standards Fig. 5 British Standard Form of Buttress Thread Assuming no Allowance <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Table 12 Numerical Data for British Standard Form Buttress Screw Threads <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Appendix D – Buttress Screw Thread Designations used in old ASA B1.9-1953 Standard <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" ASME B1.9-1973 Buttress Inch Screw Threads 7 deg.\/45 deg. Form with 0.6 Pitch Basic Height of Thread Engagement<\/b><\/p>\n |