
Unit:mm Bored Hole reference Minor Diameter Size (reference) Tap
Size L1 L3 L1+L3 Maximum Basic
Pipe End (Basic Diameter Position) Position away from Pipe End by (L1+L3) Size of Diameter
Maximum Minimum Minimum Straight Position
Tolerance Maximum Tolerance
| Value | Value | Value | Value | Bored Hole | ℓg | ||||||||
| ① | ② | ③ | ④ | ⑤ | ⑥ | ⑦ | ⑧ | ⑨ | ⑩ | ⑪ | ⑫ | ||
| 1/16 - 27 | NPT | 4.064 | 2.822 | 6.886 | 6.510 | 6.388 | 0.122 | 6.080 | 5.958 | 0.122 | 6.05 | 12.00 | |
| 1/8 - 27 | NPT | 4.102 | 2.822 | 6.924 | 8.857 | 8.736 | 0.122 | 8.425 | 8.303 | 0.122 | 8.39 | 12.05 | |
| 1/4 - 18 | NPT | 5.786 | 4.234 | 10.020 | 11.514 | 11.357 | 0.157 | 10.888 | 10.730 | 0.157 | 10.85 | 17.45 | |
| 3/8 - 18 | NPT | 6.096 | 4.234 | 10.330 | 14.953 | 14.796 | 0.157 | 14.308 | 14.150 | 0.157 | 14.27 | 17.65 | |
| 1/2 - 14 | NPT | 8.128 | 5.443 | 13.571 | 18.485 | 18.323 | 0.163 | 17.637 | 17.475 | 0.163 | 17.60 | 22.85 | |
| 3/4 - 14 | NPT | 8.611 | 5.443 | 14.054 | 23.831 | 23.668 | 0.163 | 22.952 | 22.790 | 0.163 | 22.91 | 22.95 | |
| 1 - 11 1/2 NPT | 10.160 | 6.627 | 16.787 | 29.868 | 29.696 | 0.173 | 28.819 | 28.647 | 0.173 | 28.78 | 27.40 | ||
| 1 1/4 - 11 1/2 NPT | 10.668 | 6.627 | 17.295 | 38.625 | 38.452 | 0.173 | 37.544 | 37.372 | 0.173 | 37.50 | 28.10 | ||
| 1 1/2 - 11 1/2 NPT | 10.668 | 6.627 | 17.295 | 44.695 | 44.522 | 0.173 | 43.614 | 43.441 | 0.173 | 43.57 | 28.40 | ||
| 2 - 11 1/2 NPT | 11.074 | 6.627 | 17.701 | 56.732 | 56.560 | 0.173 | 55.626 | 55.454 | 0.173 | 55.58 | 28.00 | ||
| 2 1/2 - 8 | NPT | 17.323 | 6.350 | 23.673 | 67.806 | 67.618 | 0.188 | 66.326 | 66.138 | 0.188 | 66.28 | 40.80 | |
| 3 - 8 | NPT | 19.456 | 6.350 | 25.806 | 83.715 | 83.527 | 0.188 | 82.102 | 81.914 | 0.188 | 82.05 | 42.95 |
Remarks 1. Pipe End is Basic Diameter Position (E1). Remarks 2. Effective Thread Length is the length away from Pipe End by (L1+L3). Remarks 3. C o n c e r n i n g b o r e d h o l e s h a p e , NPT INTERNAL THREAD considering load on taps, taper bored hole is recommended. L3 L1 Remarks 4. When applying taper bored hole, by referring to values in shown columns ⑤ , ⑥ and ⑧ , ⑨ , prepare the taper NPT EXTERNAL THREAD hole by using pipe reamer (1/16 taper). By referring to values shown in 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.
Technical Inf