接头数字或尺寸 NC26(2-3/8" IF) NC31(2-7/8" IF) NC38(3-1/2" IF) NC46(4" IF) NC50(4-1/2" IF) 2-7/8"FH 3-1/2"FH 对应钻具及钻头 国内编码 公端根径(mm) 73.1 公端小径(mm) 60.4 公扣长度(mm) 76.2 母扣内径(mm) 74.6 母扣长度(mm) 79.4 2-3/8" DP 2A11×2A10 2-7/8" DP 211×210 86.1 71.3 88.9 87.7 92.1 3-1/2" DP 5" DP 311×310 4A11×4A10 411×410 221×220 321×320 102 122.8 133.4 92.1 101.4 85.1 103.7 114.3 70.1 77.6 101.6 114.3 114.3 88 95.2 103.6 124.6 134.9 94.5 102.8 104.8 117.5 117.5 95 98.4 4-1/2"FH 5-1/2"FH 6-5/8"FH 2-3/8"REG 2-7/8"REG 3-1/2"REG 4-1/2"REG 5-1/2"REG 6-5/8"REG 7-5/8"REG 8-5/8"REG 7"DC 3-3/4" BIT 6-1/8" BIT 8-1/2" BIT 12-1/4"BIT/8"DC 17-1/2"BIT 421×420 521×520 621×620 2A31×2A30 231×230 331×330 431×430 531×530 631×630 731×730 831×830 121.7 148 171.5 66.7 76.2 88.9 117.5 140.2 152.2 177.8 202 96.3 126.8 150.4 47.6 54 65.1 90.5 110.1 131 144.5 167.8 101.6 127 127 76.2 88.9 95.2 108 120.6 127 133.4 136.5 123.8 150.5 173.8 68.3 77.8 90.5 119.1 141.7 154 180.2 204.4 104.8 130.2 130.2 79.4 92.1 98.4 111.1 123.8 130.2 136.5 139.7 本文来源：https://www.wddqw.com/doc/210db528647d27284b73518c.html