Tap Drill Reference Imperial Tap Drill Chart Machine Screw Size Number of Threads Per Inch Minor Dia. Tap Drills Clearance Hole Drills Aluminum, Brass & Plastics 75% Thread Stainless Steel, Steels & Iron 50% Thread All Materials Close Fit Free Fit No. or Dia. Major Dia. Drill Size Decimal Equiv. Drill Size Decimal Equiv. Drill Size Decimal Equiv. Drill Size Decimal Equiv. 0 .0600 80 .0447 3/64 .0469 55 .0520 52 .0635 50 .0700 1 .0730 64 .0538 53 .0595 1/16 .0625 48 .0760 46 .0810 72 .0560 53 .0595 52 .0635 2 .0860 56 .0641 50 .0700 49 .0730 43 .0890 41 .0960 64 .0668 50 .0700 48 .0760 3 .0990 48 .0734 47 .0785 44 .0860 37 .1040 35 .1100 56 .0771 45 .0820 43 .0890 4 .1120 40 .0813 43 .0890 41 .0960 32 .1160 30 .1285 48 .0864 42 .0935 40 .0980 5 .1250 40 .0943 38 .1015 7/64 .1094 30 .1285 29 .1360 44 .0971 37 .1040 35 .1100 6 .1380 32 .0997 36 .1065 32 .1160 27 .1440 25 .1495 40 .1073 33 .1130 31 .1200 8 .1640 32 .1257 29 .1360 27 .1440 18 .1695 16 .1770 36 .1299 29 .1360 26 .1470 10 .1900 24 .1389 25 .1495 20 .1610 9 .1960 7 .2010 32 .1517 21 .1590 18 .1695 12 .2160 24 .1649 16 .1770 12 .1890 2 .2210 1 .2280 28 .1722 14 .1820 10 .1935 32 .1777 13 .1850 9 .1960 1/4 .2500 20 .1887 7 .2010 7/32 .2188 F .2570 H .2660 28 .2062 3 .2130 1 .2280 32 .2117 7/32 .2188 1 .2280 5/16 .3125 18 .2443 F .2570 J .2770 P .3230 Q .3320 24 .2614 I .2720 9/32 .2812 32 .2742 9/32 .2812 L .2900 3/8 .3750 16 .2983 5/16 .3125 Q .3320 W .3860 X .3970 24 .3239 Q .3320 S .3480 32 .3367 11/32 .3438 T .3580 7/16 .4375 14 .3499 U .3680 25/64 .3906 29/64 .4531 15/32 .4687 20 .3762 25/64 .3906 13/32 .4062 28 .3937 Y .4040 Z .4130 1/2 .5000 13 .4056 27/64 .4219 29/64 .4531 33/64 .5156 17/32 .5312 20 .4387 29/64 .4531 15/32 .4688 28 .4562 15/32 .4688 15/32 .4688 9/16 .5625 12 .4603 31/64 .4844 33/64 .5156 37/64 .5781 19/32 .5938 18 .4943 33/64 .5156 17/32 .5312 24 .5114 33/64 .5156 17/32 .5312 5/8 .6250 11 .5135 17/32 .5312 9/16 .5625 41/64 .6406 21/32 .6562 18 .5568 37/64 .5781 19/32 .5938 24 .5739 37/64 .5781 19/32 .5938 11/16 .6875 24 .6364 41/64 .6406 21/32 .6562 45/64 .7031 23/32 .7188 3/4 .7500 10 .6273 21/32 .6562 11/16 .6875 49/64 .7656 25/32 .7812 16 .6733 11/16 .6875 45/64 .7031 20 .6887 45/64 .7031 23/32 .7188 1-3/16 .8125 20 .7512 49/64 .7656 25/32 .7812 53/64 .8281 27/32 .8438 7/8 .8750 9 .7387 49/64 .7656 51/64 .7969 57/64 .8906 29/32 .9062 14 .7874 13/16 .8125 53/64 .8281 20 .8137 53/64 .8281 27/32 .8438 15/16 .9375 20 .8762 57/64 .8906 29/32 .9062 61/64 .9531 31/32 .9688 1 1.000 8 .8466 7/8 .8750 59/64 .9219 1-1/64 1.0156 1-1/32 1.0313 12 .8978 15/16 .9375 61/64 .9531 20 .9387 61/64 .9531 31/32 .9688 1-1/16 1.0625 18 .9943 1.000 1.000 1-1/64 1.0156 1-5/64 1.0781 1-3/32 1.0938 1-1/8 1.1250 7 .9497 63/64 .9844 1-1/32 1.0313 1-9/64 1.1406 1-5/32 1.1562 12 1.0228 1-3/64 1.0469 1-5/64 1.0781 18 1.0568 1-1/16 1.0625 1-5/64 1.0781 1-3/16 1.1875 18 1.1193 1-1/8 1.1250 1-9/64 1.1406 1-13/64 1.2031 1-7/32 1.2188 1-1/4 1.2500 7 1.0747 1-7/64 1.1094 1-5/32 1.1562 1-17/64 1.2656 1-9/32 1.2812 12 1.1478 1-11/64 1.1719 1-13/64 1.2031 18 1.1818 1-3/16 1.1875 1-13/64 1.2031 1-5/16 1.3125 18 1.2443 1-1/4 1.2500 1-17/64 1.2656 1-21/64 1.3281 1-11/32 1.3438 1-3/8 1.3750 6 1.1705 1-7/32 1.2187 1-17/64 1.2656 1-25/64 1.3906 1-13/32 1.4062 12 1.2728 1-19/64 1.2969 1-21/64 1.3281 18 1.3068 1-5/16 1.3125 1-21/64 1.3281 1-7/16 1.4375 18 1.3693 1-3/8 1.3750 1-25/64 1.3906 1-29/64 1.4531 1-15/32 1.4688 1-1/2 1.500 6 1.2955 1-11/32 1.3437 1-25/64 1.3906 1-33/64 1.5156 1-17/32 1.5312 12 1.3978 1-27/64 1.4219 1-7/16 1.4375 18 1.4318 1-7/16 1.4375 1-29/64 1.4531 1-9/16 1.5625 18 1.4943 1-12 1.500 1-33/64 1.5156 1-37/64 1.5781 1-19/32 1.5938 1-5/8 1.625 18 1.5568 1-9/16 1.5625 1-37/64 1.5781 1-41/64 1.6406 1-21/32 1.6562 1-11/16 1.6875 18 1.6193 1-5/8 1.6250 1-41/64 1.6406 1-45/64 1.7031 1-23/32 1.7188 1-3/4 1.750 5 1.5046 1-9/16 1.5625 1-5/8 1.6250 1-49/64 1.7659 1-25/32 1.7812 Metric Tap Drill Chart Tap size Major Dia (mm) Threads per Tap Drill (mm) Tap Drill (inch) Clearance (mm) Clearance (inch) M1.6×0.35 1.6 0.35 1.25 #55 1.8 #49 M2x0.4 2.0 0.40 1.60 #52 2.4 #41 M2.5×0.45 2.5 0.45 2.05 #46 2.9 #32 M3x.05 3.0 0.50 2.50 #39 3.4 #29 M3.5×0.6 3.5 0.60 2.90 #32 3.9 #23 M4x0.7 4.0 0.70 3.30 #30 4.5 #16 M5x0.8 5.0 0.80 4.20 #19 5.5 7/32 M6x1 6.0 1.00 5.0 #8 6.6 G M8x1.25 8.0 1.25 6.8 H 9.0 T M8x1 8.0 1.00 7.0 J 9.0 T M10x1.5 10.0 1.50 8.5 R 12.0 31/64 M10x1.25 10.0 1.25 8.8 11/32 12.0 31/64 M12x1.75 12.0 1.75 10.2 13/32 14.0 35/64 M12x1.25 12.0 1.25 10.8 27/64 14.0 35/64 M14x2 14.0 2.00 12.0 15/32 16.0 5/8 M14x1.5 14.0 1.5 12.5 1/2 16.0 5/8 M16x2 16.0 2.00 14.0 35/64 18.0 45/64 M16x1.5 16.0 1.50 14.5 37/64 18.0 45/64 M18x2.5 18.0 2.50 15.5 39/64 20.0 51/64 M18x1.5 18.0 1.50 16.5 21/32 20.0 51/64 M20x2.5 20.0 2.50 17.5 11/16 22.0 7/8 M20x1.5 20.0 1.50 18.5 47/64 22.0 7/8 M22x2.5 22.0 2.50 19.5 49/64 25.0 1 M22x1.5 22.0 1.50 20.5 13/16 25.0 1 M24x3 24.0 3.00 21.0 53/64 27.0 1-5/64 M24x2 24.0 2.00 22.0 7/8 27.0 1-5/64 M27x3 27.0 3.00 24.0 15/16 30.0 1-3/16 M27x2 27.0 2.0 25.0 1 30.0 1-3/16 Pipe Threads – American Standard British Standard Nominal OD Threads per inch NPT NPS Threads per inch Drill size 1/16 27 D 1/4 28 G 1/8 27 R S 28 11/32 1/4 18 7/16 29/64 19 15/32 3/8 18 37/64 19/32 19 39/64 1/2 14 23/32 47/64 14 3/4 5/8 – – – 14 53/64 3/4 14 59/64 15/16 14 31/32 7/8 – – – 14 1-7/64 1 11.5 1-5/32 1-3/16 11 1-7/32 Drill Chart – Standard Drill Sizes / Millimeter Sizes (See typical tolerances of drilled holes at bottom of page) Drill (in.) Decimal Drill (in.) Decimal Drill (in.) Decimal Drill (mm) Decimal (in.) Drill (mm) Decimal (in.) Drill (mm) Decimal (in.) 80 .0135 1/8 .1250 O .3160 .35 .0138 3.4 .1339 8.0 .3150 79 .0145 30 .1285 P .3230 .4 .0157 3.5 .1378 8.1 .3189 1/64 .0156 29 .1360 21/64 .3281 .45 .0177 3.6 .1417 8.2 .3228 78 .0160 28 .1405 Q .3320 .5 .0197 3.7 .1457 8.25 .3248 77 .0180 9/64 .1406 R .3390 .55 .0217 3.75 .1477 8.3 .3267 76 .0200 27 .1440 11/32 .3437 .6 .0236 3.8 .1496 8.4 .3307 75 .0210 26 .1470 S .3480 .65 .0256 3.9 .1535 8.5 .3346 74 .0225 25 .1495 T .3580 .7 .0276 4.0 .1575 8.6 .3386 73 .0240 24 .1520 23/64 .3594 .75 .0295 4.1 .1614 8.7 .3425 72 .0250 23 .1540 U .3680 .8 .0315 4.2 .1654 8.75 .3445 71 .0260 5/32 .1562 3/8 .3750 .85 .0335 4.25 .1674 8.8 .3465 70 .0280 22 .1570 V .3770 .9 .0355 4.3 .1693 8.9 .3504 69 .0292 21 .1590 W .3860 .95 .0374 4.4 .1732 9.0 .3543 68 .0310 20 .1610 25/64 .3906 1.0 .0394 4.5 .1771 9.1 .3583 1/32 .0313 19 .1660 X .3970 1.05 .0413 4.6 .1811 9.2 .3622 67 .0320 18 .1695 Y .4040 1.1 .0433 4.7 .1850 9.25 .3642 66 .0330 11/64 .1719 13/32 .4062 1.15 .0453 4.75 .1870 9.35 .3661 65 .0350 17 .1730 Z .4130 1.2 .0472 4.8 .1890 9.4 .3701 64 .0360 16 .1770 27/64 .4219 1.25 .0492 4.9 .1929 9.5 .3740 63 .0370 15 .1800 7/16 .4375 1.3 .0512 5.0 .1968 9.6 .3780 62 .0380 14 .1820 29/64 .4531 1.35 .0531 5.1 .2008 9.7 .3819 61 .0390 13 .1850 15/32 .4687 1.4 .0551 5.2 .2047 9.75 .3839 60 .0400 3/16 .1875 31/64 .4844 1.45 .0571 5.25 .2067 9.8 .3858 59 .0410 12 .1890 � .5000 1.5 .0591 5.3 .2087 9.9 .3898 58 .0420 11 .1910 33/64 .5156 1.55 .0610 5.4 .2126 10.0 .3937 57 .0430 10 .1935 17/32 .5312 1.6 .0629 5.5 .2165 10.5 .4133 56 .0465 9 .1960 35/64 .5469 1.65 .0650 5.6 .2205 11.0 .4331 3/64 .0469 8 .1990 9/16 .5625 1.7 .0669 5.7 .2244 11.5 .4528 55 .0520 7 .2010 37/64 .5781 1.75 .0689 5.75 .2264 12.0 .4724 54 .0550 13/64 .2031 19/32 .5937 1.8 .0709 5.8 .2283 12.5 .4921 53 .0595 6 .2040 39/64 .6094 1.85 .0728 5.9 .2323 13.0 .5118 1/16 .0625 5 .2055 5/8 .6250 1.9 .0748 6.0 .2362 13.5 .5315 52 .0635 4 .2090 41/64 .6406 1.95 .0768 6.1 .2401 14.0 .5512 51 .0670 3 .2130 21/32 .6562 2.0 .0787 6.2 .2441 14.5 .5708 50 .0700 7/32 .2187 43/64 .6719 2.05 .0807 6.25 .2461 15.0 .5906 49 .0730 2 .2210 11/16 .6875 2.1 .0827 6.3 .2480 15.5 .6102 48 .0760 1 .2280 45/64 .7031 2.15 .0846 6.4 .2520 16.0 .6300 5/64 .0781 A .2340 23/32 .7187 2.2 .0866 6.5 .2559 16.5 .6496 47 .0785 15/64 .2344 47/64 .7344 2.25 .0886 6.6 .2598 17.0 .6693 46 .0810 B .2380 � .7500 2.3 .0905 6.7 .2638 17.5 .6889 45 .0820 C .2420 49/64 .7656 2.35 .0925 6.75 .2658 18.0 .7087 44 .0860 D .2460 25/32 .7812 2.4 .0945 6.8 .2677 18.5 .7283 43 .0890 E .2500 51/64 .7969 2.45 .0965 6.9 .2716 19.0 .7480 42 .0935 � .2500 13/16 .8125 2.5 .0984 7.0 .2756 19.5 .7677 3/32 .0937 F .2570 53/64 .8281 2.55 .1004 7.1 .2795 20.0 .7874 41 .0960 G .2610 27/32 .8437 2.6 .1024 7.2 .2835 20.5 .8071 40 .0980 17/64 .2656 55/64 .8594 2.65 .1043 7.25 .2855 21.0 .8268 39 .0995 H .2660 7/8 .8750 2.7 .1063 7.3 .2874 21.5 .8465 38 .1015 I .2720 57/64 .8906 2.75 .1083 7.4 .2913 22.0 .8661 37 .1040 J .2770 29/32 .9062 2.8 .1102 7.5 .2953 22.5 .8858 36 .1065 K .2811 59/64 .9219 2.9 .1142 7.6 .2990 23.0 .9055 7/64 .1093 9/32 .2812 15/16 .9375 3.0 .1181 7.7 .3031 23.5 .9252 35 .1100 L .2900 61/64 .9531 3.1 .1220 7.75 .3051 24.0 .9449 34 .1110 M .2950 31/32 .9687 3.2 .1260 7.8 .3071 24.5 .9646 33 .1130 19/64 .2968 63/64 .9844 3.25 .1280 7.9 .3110 25.0 .9843 32 .1160 N .3020 1 1.000 3.3 .1299 31 .1200 5/16 .3125