美制粗螺纹 规格 (UNC) NO.1-64(1.854) NO.2-56(2.184) NO.3-48(2.515) NO.4-40(2.845) NO.5-40(3.175) NO.6-32(3.505) NO.8-32(4.166) NO.10-24(4.826) NO.12-24(5.486) 1/4 -20 5/16 -18 3/8 -16 7/16 -14 1/2 -13 9/16 -12 5/8 -11 3/4 -10 7/8 -9 1-8 1-1/8-7 1-1/4-7 1-3/8-6 1-1/2-6 1-3/4-5 2-4-1/2 2级牙钻孔径 标准径 1.55 1.80 2.10 2.30 2.60 2.80 3.40 3.90 4.50 5.10 6.60 8.00 9.40 10.80 12.20 13.60 16.50 19.50 22.20 25.00 28.20 30.80 34.00 39.50 45.20 最大 1.582 1.871 2.146 2.385 2.697 2.895 3.530 3.962 4.597 5.257 6.731 8.153 9.550 11.023 12.446 12.868 18.840 19.761 22.606 25.349 28.524 31.115 34.290 39.827 45.593 最小 1.425 1.695 1.941 2.157 2.487 2.642 3.302 3.683 4.344 4.979 6.401 7.798 9.144 10.592 11.989 13.386 16.307 19.177 21.971 24.638 27.813 30.353 33.528 38.964 44.679 规格 (UNF) NO.0-80(1.524) NO.1-72(1.854) NO.2-64(2.184) NO.3-56(2.515) NO.4-48(2.845) NO.5-44(3.175) NO.6-40(3.505) NO.8-36(4.166) NO.10-32(4.826) NO.12-28(5.846) 1/4-28 5/16-24 3/8-24 7/16-20 1/2-20 9/16-18 5/8-18 3/4-16 7/8-14 1-12 1-1/8-12 1-1