锥管螺纹的尺寸是通过表查的,无需公式计算.看看这个吧

　　°圆锥管螺纹(BSPT)

　　螺纹代号

　　基本尺寸

　　英寸大径

　　mm

　　d=D螺距

　　mm

　　p每英寸牙数

　　tpi中径

　　mm

　　d2=D2小径

　　外螺纹

　　d3牙型高度

　　H1圆弧尺寸

　　r底孔尺寸

　　mm

　　R1/161/16"7.7230.907287.1426.5610.5810.1256.4

　　R1/81/8"9.7280.907289.1478.5660.5810.1258.4

　　R1/41/4"13.1571.3371912.30111.4450.8560.18411.2

　　R3/83/8"16.6621.3371915.80614.9500.8560.18414.75

　　R1/21/2"20.9551.8141419.79318.6311.1620.24918.25

　　R3/43/4"26.4411.8141425.27924.1171.1620.24923.75

　　R11"33.2492.3091131.7730.2911.4790.31730

　　R11/411/4"41.9102.3091140.43138.9521.4790.31738.5

　　R11/211/2"47.8032.3091146.32444.8451.4790.31744.5

　　R22"59.6142.3091158.13556.6561.4790.31756

　　R21/221/2"75.1842.3091173.70572.2261.4790.31771

　　R33"87.8842.3091186.40584.9261.4790.31785.5

　　R44"113.0302.30911111.551110.0721.4790.317110.5

　　R55"138.4302.30911136.951135.4721.4790.317136

　　R66"163.8302.30911162.351160.8721.4790.317161.5