Resources

Drill Size Conversion Table


This table is the chart for converting and identifying various drill bit sizes.

Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)
Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)
Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)
 0.0098 0.25  0.106536   0.3480S 
 0.0118 0.30 7/640.1094    0.3543 9.00
 0.013580   0.110035   0.3580T 
 0.0138 0.35  0.1102 2.80 23/640.3594  
 0.014579   0.111034   0.3680U 
1/640.0156    0.113033   0.3740 9.50
 0.0157 0.40  0.1142 2.90 3/80.3750  
 0.016078   0.116032   0.3770V 
 0.0177 0.45  0.1181 3.00  0.3860W 
 0.018077   0.120031  25/640.3906  
 0.0197 0.50 1/80.1250    0.3937 10.00
 0.020076   0.128530   0.3970X 
 0.021075   0.136029   0.4040Y 
 0.0217 0.55  0.1378 3.50 13/320.4063  
 0.022574   0.140528   0.4130Z 
 0.0236 0.60 9/640.1406    0.4134 10.50
 0.024073   0.144027  27/640.4219  
 0.025072   0.147026   0.4331 11.00
 0.0256 0.65  0.149525  7/160.4375  
 0.026071   0.152024   0.4528 11.50
 0.0276 0.70  0.154023  29/640.4531  
 0.028070  5/320.1563   15/320.4688  
 0.029269   0.157022   0.4724 12.00
 0.0295 0.75  0.1575 4.00 31/640.4844  
 0.031068   0.159021   0.4921 12.50
1/320.0313    0.161020  1/20.5000  
 0.0315 0.80  0.166019   0.5118 13.00
 0.032067   0.169518  33/640.5156  
 0.033066  11/640.1719   17/320.5313  
 0.0335 0.85  0.173017   0.5315 13.50
 0.035065   0.177016  35/640.5469  
 0.0354 0.90  0.1772 4.50  0.5512 14.00
 0.036064   0.180015  9/160.5625  
 0.037063   0.182014   0.5709 14.50
 0.0374 0.95  0.185013  37/640.5781  
 0.038062  3/160.1875    0.5905 15.00
 0.039061   0.189012  19/320.5938  
 0.0394 1.00  0.191011  39/640.6094  
 0.040060   0.193510   0.6102 15.50
 0.041059   0.19609  5/80.6250  
 0.042058   0.1968 5.00  0.6299 16.00
 0.043057   0.19908  41/640.6406  
 0.0433 1.10  0.20107   0.6496 16.50
 0.046556  13/640.2031   21/320.6563  
3/640.0469    0.20406   0.6693 17.00
 0.0472 1.20  0.20555  43/640.6719  
 0.0512 1.30  0.20904  11/160.6875  
 0.052055   0.21303   0.6890 17.50
 0.055054   0.2165 5.50 45/640.7031  
 0.0551 1.40 7/320.2188    0.7087 18.00
 0.0591 1.50  0.22102  23/320.7188  
 0.059553   0.22801   0.7283 18.50
1/160.0625    0.2340A  47/640.7344  
 0.0630 1.60 15/640.2344    0.7480 19.00
 0.063552   0.2362 6.00 3/40.7500  
 0.0669 1.70  0.2380B  49/640.7656  
 0.067051   0.2420C   0.7677 19.50
 0.070050   0.2460D  25/320.7813  
 0.0709 1.80 1/40.2500E   0.7874 20.00
 0.073049   0.2559 6.50 51/640.7969  
 0.0748 1.90  0.2570F   0.8071 20.50
 0.076048   0.2610G  13/160.8125  
5/640.0781   17/640.2656    0.8268 21.00
 0.078547   0.2660H  53/640.8281  
 0.0787 2.00  0.2720I  27/320.8438  
 0.081046   0.2756 7.00  0.8465 21.50
 0.082045   0.2770J  55/640.8594  
 0.0827 2.10  0.2810K   0.8661 22.00
 0.086044  9/320.2813   7/80.8750  
 0.0866 2.20  0.2900L   0.8858 22.50
 0.089043   0.2950M  57/640.8906  
 0.0906 2.30  0.2953 7.50  0.9055 23.00
 0.093542  19/640.2969   29/320.9063  
3/320.0938    0.3020N  59/640.9219  
 0.0945 2.40 5/160.3125    0.9252 23.50
 0.096041   0.3150 8.00 15/160.9375  
 0.098040   0.3160O   0.9449 24.00
 0.0984 2.50  0.3230P  61/640.9531  
 0.099539  21/640.3281    0.9646 24.50
 0.101538   0.3320Q  31/320.9688  
 0.1024 2.60  0.3346 8.50  0.9842 25.00
 0.104037   0.3390R  63/640.9844  
 0.1063 2.70 11/320.3438   11.0000  
Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)
Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)
Fract.
(in)
DecimalWire No.
/Letter
Metric
(mm)

THREAD/SCREW - Drill & Tap Chart

Machine Screw
Size
Threads
Per Inch
Minor
Dia
Tap Drills Clearance Hole Drills
Alum, Brass,
& Plasitcs

75% Thread

Stainless Steel,
Steels & Iron

50% Thread

All Materials
Close Fit Free Fit
# 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 .125 40 .0943 38 .1015 7/64 .1094 30 .1285 29 .1360
44 .0971 37 .1040 35 .1100
6 .138 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 .6562
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
13/16 .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



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