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Imperial Tap Chart

Screw Size Specifications Tap Drill Clearance Drill
Aluminum, Brass & Plastics Steel, Stainless Steel & Iron Close Fit Standard Fit
75% Thread 50% Thread
No. or Dia. Major Dia. TPI Series Minor Dia. Drill Size Decimal Drill Size Decimal Drill Size Decimal Drill Size Decimal
000 .0340 120 NS .0232 71 .026 71 .0260 65 .0350 62 .0380
00 0.0470 90 NS .0334 65 .0350 61 .0390 3/64 0.0469 55 0.0520
0 0.060 80 NF .0465 3/64 0.0469 55 0.0520 52 0.0635 50 0.070
1 0.073 56 NS .0498 54 0.055     48 0.076 46 0.081
64 NC 0.0538 53 0.0595 1/16 0.0625
72 NF 0.056 53 0.0595 52 0.0635
2 0.086 56 NC 0.0641 50 0.07 49 0.073 43 0.089 41 0.096
64 NF 0.0668 50 0.07 48 0.076
3 0.099 48 NC 0.0734 47 0.0785 44 0.086 37 0.104 35 0.110
56 NF 0.0771 45 0.082 43 0.089
4 0.112 40 NC 0.0813 43 0.089 41 0.096 32 0.116 30 0.1285
48 NF 0.0864 42 0.0935 40 0.098
5 0.125 40 NC 0.0943 38 0.1015 9/64 0.1094 30 0.1285 29 0.136
44 NF 0.0971 37 0.104 35 0.110
6 0.138 32 NC 0.0997 36 0.1065 32 0.116 27 0.144 25 0.1495
40 NF 0.1073 33 0.113 31 0.120
8 0.164 32 NC 0.1257 29 0.136 27 0.144 18 0.1695 16 0.177
36 NF 0.1299 29 0.136 26 0.147
10 0.190 24 NC 0.1389 25 0.1495 20 0.161 9 0.196 7 0.201
32 NF 0.1517 21 0.159 18 0.1695
12 0.216 24 NC 0.1649 16 0.177 12 0.189 2 0.221 1 0.228
28 NF 0.1722 14 0.182 10 0.1935
32 NEF 0.1777 13 0.185 9 0.196
1/4 0.250 20 NC 0.1887 7 0.201 7/32 0.2188 F 0.257 H 0.266
28 NF 0.2062 3 0.213 1 0.228
32 NEF 0.2117 7/32 0.2188 1 0.228
5/16 0.3125 18 NC 0.2443 F 0.257 J 0.277 P 0.323 Q 0.332
24 NF 0.2614 I 0.272 9/32 0.2812
32 NEF 0.2742 9/32 0.2812 L 0.290
3/8 0.375 16 NC 0.2983 5/16 0.3125 Q 0.332 W 0.386 X 0.397
24 NF 0.3239 Q 0.332 S 0.348
32 NEF 0.3367 11/32 0.3438 T 0.358
7/16 0.4375 14 NC 0.3499 U 0.368 25/64 0.3906 29/64 0.4531 15/32 0.4687
20 NF 0.3762 25/64 0.3906 13/32 0.4062
28 NEF 0.3937 Y 0.404 Z 0.413
1/2 0.500 13 NC 0.4056 27/64 0.4219 29/64 0.4531 33/64 0.5156 17/32 0.5312
20 NF 0.4387 29/64 0.4531 15/32 0.4688
28 NEF 0.4562 15/32 0.4688 15/32 0.4688
9/16 0.5625 12 NC 0.4603 31/64 0.4844 33/64 0.5156 37/64 0.5781 19/32 0.5938
18 NF 0.4943 33/64 0.5156 17/32 0.5312
24 NEF 0.5114 33/64 0.5156 17/32 0.5312
5/8 0.625 11 NC 0.5135 17/32 0.5312 41168 0.5625 41/64 0.6406 21/32 0.6562
18 NF 0.5568 37/64 0.5781 19/32 0.5938
24 NEF 0.5739 37/64 0.5781 19/32 0.5938
11/16 0.6875 24   0.6364 41/64 0.6406 21/32 0.6562 45/64 0.7031 23/32 0.7188
3/4 0.750 10 NC 0.6273 21/32 0.6562 11/16 0.6875 49/64 0.7656 25/32 0.7812
16 NF 0.6733 11/16 0.6875 45/64 0.7031
20 NEF 0.6887 45/64 0.7031 23/32 0.7188
13/16 0.8125 20   0.7512 49/64 0.7656 25/32 0.7812 53/64 0.8281 27/32 0.8438
7/8 0.875 9 NC 0.7387 49/64 0.7656 51/64 0.7969 57/64 0.8906 29/32 0.9062
14 NF 0.7874 13/16 0.8125 53/64 0.8281
20 NEF 0.8137 53/64 0.8281 27/32 0.8438
15/16 0.9375 20   0.8762 57/64 0.8906 29/32 0.9062 61/64 0.9531 31/32 0.9688
1 1.000 8 NC 0.8466 7/8 0.875 59/64 0.9219 1-1/64 1.0156 1-31/32 1.0313
12 NF 0.8978 15/16 0.9375 61/64 0.9531
20 NEF 0.9387 61/64 0.9531 31/32 0.9688
1-1/16 1.0625 18 NEF 0.9943 1 1 1-1/64 1.0156 1-5/64 1.0781 1-3/32 1.0938
1-1/8 1.125 7 NC 0.9497 63/64 0.9844 1-1/32 1.0313 1-9/64 1.1406 1-5/32 1.1562
12 NF 1.0228 1-3/64 1.0469 1-5/64 1.0781
18 NEF 1.0568 1-1/16 1.0625 1-5/64 1.0781
1-3/16 1.1875 18 NEF 1.1193 49/64 1.125 1-9/64 1.1406 1-13/64 1.2031 1-7/32 1.2188
1-1/4 1.250 7 NC 1.0747 1-7/64 1.1094 1-5/32 1.1562 1-17/64 1.2656 1-9/32 1.2812
12 NF 1.1478 1-11/64 1.1719 1-13/64 1.2031
18 NEF 1.1818 1-3/16 1.1875 1-13/64 1.2031
1-5/16 1.3125 18 NEF 1.2443 1-1/4 1.25 1-17/64 1.2656 1-21/64 1.3281 1-11/32 1.3438
1-3/8 1.375 6 NC 1.1705 1-7/32 1.2187 1-17/64 1.2656 1-25/64 1.3906 1-13/32 1.4062
12 NF 1.2728 1-19/64 1.2969 1-21/64 1.3281
18 NEF 1.3068 1-5/16 1.3125 1-21/64 1.3281
1-7/16 1.4375 18 NEF 1.3693 1-3/8 1.375 1-25/64 1.3906 1-29/64 1.4531 1-15/32 1.4688
1-1/2 1.500 6 NC 1.2955 1-11/32 1.3437 1-25/64 1.3906 1-33/64 1.5156 1-17/32 1.5312
12 NF 1.3978 1-27/64 1.4219 1-7/16 1.4375
18 NEF 1.4318 1-7/16 1.4375 1-29/64 1.4531
1-9/16 1.5625 18 NEF 1.4943 1-1/2 1.5 1-33/64 1.5156 1-37/64 1.5781 1-19/32 1.5938
1-5/8 1.625 18 NEF 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 NEF 1.6193 1-5/8 1.625 1-41/64 1.6406 1-45/64 1.7031 1-23/32 1.7188
1-3/4 1.750 5 NC 1.5046 1-9/16 1.5625 1-5/8 1.625 1-49/64 1.7659 1-25/32 1.7812

 

 
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