NPT圆锥管螺纹的基本尺寸

螺纹   1/16  1/8  1/4  3/8  1/2  3/4 1 1–1/4 1–1/2 2 2–1/2 3
牙数 27 27 18 18 14 14 11.5 11.5 11.5 11.5 8 8
螺距 / mm 0.941 0.941 1.411 1.411 1.814 1.814 2.209 2.209 2.209 2.209 3.175 3.175
牙型高度 / mm 0.753 0.753 1.129 1.129 1.451 1.451 1.767 1.767 1.767 1.767 2.54 2.54
大径 d = D / mm 7.895 10.242 13.616 17.055 21.223 26.568 33.228 41.985 48.054 60.092 72.699 88.608
中径 d2 = D2 / mm 7.142 9.489 12.487 15.926 19.772 25.117 31.461 40.218 46.287 58.325 70.159 86.068
小径 d1 = D1 / mm 6.389 8.736 11.358 14.797 18.321 23.666 29.694 38.451 44.52 56.558 67.619 83.528
基准距离 螺纹数量 4.32 4.36 4.1 4.32 4.48 4.75 4.6 4.83 4.83 5.01 5.46 6.13
基准距离 L1 / mm 4.064 4.102 5.786 6.096 8.128 8.611 10.16 10.668 10.668 11.074 17.323 19.456
装配余量距离 螺纹数量 3 3 3 3 3 3 3 3 3 3 2 2
装配距离 L3 / mm 2.822 2.822 4.234 4.234 5.443 5.443 6.627 6.627 6.627 6.627 6.35 6.35
外螺纹小端面内的基本小径 / mm 6.137 8.481 10.996 14.417 17.813 23.127 29.06 37.785 43.853 55.867 66.535 82.311
螺纹 3–1/2 4 5 6 8 10 12 14 16 18 20 24
牙数 8 8 8 8 8 8 8 8 8 8 8 8
螺距 / mm 3.175 3.175 3.175 3.175 3.175 3.175 3.175 3.175 3.175 3.175 3.175 3.175
牙型高度 / mm 2.54 2.54 2.54 2.54 2.54 2.54 2.54 2.54 2.54 2.54 2.54 2.54
大径 d = D / mm 101.316 113.973 140.952 167.792 218.441 272.312 323.032 354.904 405.784 456.565 507.246 608.608
中径 d2 = D2 / mm 98.776 111.433 138.412 165.252 215.901 269.772 320.492 352.364 403.244 454.025 504.706 606.068
小径 d1 = D1 / mm 96.236 108.893 135.872 162.712 213.361 267.232 317.952 349.824 400.704 451.485 502.166 603.528
基准距离 螺纹数量 6.57 6.75 7.5 7.66 8.5 9.68 10.88 12.5 14.5 16 17 19
基准距离 L1 / mm 20.853 21.438 23.8 24.333 27 30.734 34.544 39.675 46.025 50.8 53.975 60.325
装配余量距离 螺纹数量 2 2 2 2 2 2 2 2 2 2 2 2
装配距离 L3 / mm 6.35 6.35 6.35 6.35 6.35 6.35 6.35 6.35 6.35 6.35 6.35 6.35
外螺纹小端面内的基本小径 / mm 94.933 107.554 134.384 161.191 211.673 265.311 315.793 347.345 397.828 448.31 498.793 599.758