Обший каталог Yamawa 2016 - 2017 - страница 819

Предыдущая страница Следующая страница

Навигация

15. Bored hole size before tapping ( for thread cutting ) ■ Recommended Bored Hole Size Table for American Dryseal Taper Pipe Threads (NPTF) (Refer to ANSI B1.20.3-1976, re-confirmed in 1982) Production data unit: mm Bored Hole reference Minor Diameter Size Tap L3 (reference) Size L1 (3P) L1+L3+1P Pipe End Position of Maximum Basic (Basic Diameter Position) ( L1+L3+1P ) Size of Diameter Maximum Minimum Tolerance Maximum Minimum Tolerance Straight Position Value Value Value Value Bored Hole ℓg ① ② ③ ④ ⑤ ⑥ ⑦ ⑧ ⑨ ⑩ ⑪ ⑫ NPTF 1/16 - 27 4.064 2.822 7.827 6.505 6.414 0.091 6.015 5.923 0.091 5.99 12.00 NPTF 1/8 - 27 4.102 2.822 7.865 8.852 8.761 0.091 8.362 8.270 0.091 8.34 12.05 NPTF 1/4 - 18 5.786 4.234 11.431 11.484 11.397 0.086 10.770 10.684 0.086 10.75 17.45 NPTF 3/8 - 18 6.096 4.234 11.741 14.923 14.836 0.086 14.189 14.103 0.086 14.17 17.65 NPTF 1/2 - 14 8.128 5.443 15.386 18.419 18.333 0.086 17.459 17.373 0.086 17.44 22.85 NPTF 3/4 - 14 8.611 5.443 15.868 23.764 23.678 0.086 22.773 22.687 0.086 22.75 22.95 NPTF 1- 11.5 10.160 6.627 18.996 29.812 29.726 0.086 28.625 28.538 0.086 28.60 27.40 NPTF 11/4 - 11.5 10.668 6.627 19.504 38.569 38.483 0.086 37.350 37.263 0.086 37.33 28.10 NPTF 11/2 - 11.5 10.668 6.627 19.504 44.639 44.552 0.086 43.420 43.334 0.086 43.40 28.40 NPTF 2- 11.5 11.074 6.627 19.910 56.677 56.590 0.086 55.432 55.345 0.086 55.41 28.00 HAND ENGAGEMENT(L1)+L3 + ONE TURN FULL THREAD L3 3p L1 Remarks 1. Pipe End is Basic Diameter Position (E1). Remarks 2. Effective Thread Length is the length away from Pipe End by (L1+L3+1P). NPTF INTERNAL THREAD Remarks 3. Concerning bored hole shape, considering load on taps, taper bored hole is recommended. NPTF EXTERNAL THREAD Remarks 4. When applying taper bored hole, by referring to values E3 E0 E1 shown in columns ⑤, ⑥ and ⑧, ⑨, prepare the taper D hole by using pipe reamer (1/16 taper). By referring to values in shown column ⑪, select the drill diameter before reaming by taking reamer's margin into account. Remarks 5. When preparing straight bored hole, by referring to values shown in column ⑪, select drill diameter. ■Percentage of Thread Engagement & Relation between Percentage of Thread Height and Area Removed at A Thread Height Percentage of Thread Engagement percentage of Thread Height (%) percentage of Area Removed (%) internal Basic Major Dia. − Hole Size Before Tapping threads 2× (Basic Thread Overlap) 100 Basic Thread Overlap Metric & Unified Thread 0.5413P Whitworth Thread 0.5664P Information Pipe Thread (Rc, Rp, G, PT, PS, PF) 0.6403P Technical P=Pitch As shown above, when the thread height increases, the amount of material to be removed increases rapidly, so it is an advantage to tap users to keep the hole size (thread minor diameter) as large as possible. Technical-44 815