DECIMAL

D ecimal equivalents

Inch/Metric Tap Drill Sizes & Decimal Equivalents Drill Size

19 39 32 64 41 64 21 43 32 64 45 64 23 47 32 64 49 64 25 51 32 64 53 64 27 55 32 64 57 64 29 59 32 64 61 64 31 63 32 64 13/64 17/64 111/64 17/32

5 8 11 16 3 4 13 16 7 8 15 16 1 11/8 11/4

119/64 111/32 13/8 127/64 11/2

Decimal EQUIVALENT

.5938 .6094 .6250 .6406 .6562 .6719 .6875 .7031 .7188 .7344 .7500 .7656 .7812 .7969 .8125 .8281 .8438 .8594 .8750 .8906 .9062 .9219 .9375 .9531 .9688 .9844 1.0000 1.0469 1.1094 1.1250 1.1719 1.2188 1.2500 1.2969 1.3438 1.3750 1.4219 1.5000

Tap Size

3/4

- 10

3/4

- 16

7/8 7/8

-9 - 14

1-8 1 - 12 1 - 14 11/8 - 7 11/8 - 12 11/4 - 7 11/4 - 12 13/8 - 6 13/8 - 12 11/2 - 6 11/2 - 12

pipe thread Sizes (npsc) thread drill thread drill 1/8 – 27 11/32 11/2 – 111/2 13/4 1/4 – 18 7/16 2 – 111/2 27/32 3/8 – 18 37/64 21/2 – 8 21 2 /32 1/2 – 14 23/32 3–8 31/4 3/4 – 14 59/64 31/2 – 8 33/4 1 – 111/2 15/32 4–8 41/4 11/4 – 111/2 11/2

Bulletin 1317-150M/S 06/09

Metric Tap

Metric Tap Drill Sizes Tap Drill (mm) Decimal (Inch)

M1.6 x 0.35 M1.8 x 0.35 M2 x 0.4 M2.2 x 0.45 M2.5 x 0.45 M3 x 0.5 M3.5 x 0.6 M4 x 0.7 M4.5 x 0.75 M5 x 0.8 M6 x 1 M7 x 1 M8 x 1.25 M8 x 1 M10 x 1.5 M10 x 1.25 M12 x 1.75 M12 x 1.25 M14 x 2 M14 x 1.5 M16 x 2 M16 x 1.5 M18 x 2.5 M18 x 1.5 M20 x 2.5 M20 x 1.5 M22 x 2.5 M22 x 1.5 M24 x 3 M24 x 2 M27 x 3 M27 x 2 M30 x 3.5 M30 x 2 M33 x 3.5 M33 x 2 M36 x 4 M36 x 3 M39 x 4 M39 x 3

1.25 1.45 1.60 1.75 2.05 2.50 2.90 3.30 3.70 4.20 5.00 6.00 6.70 7.00 8.50 8.70 10.20 10.80 12.00 12.50 14.00 14.50 15.50 16.50 17.50 18.50 19.50 20.50 21.00 22.00 24.00 25.00 26.50 28.00 29.50 31.00 32.00 33.00 35.00 36.00

.0492 .0571 .0630 .0689 .0807 .0984 .1142 .1299 .1457 .1654 .1968 .2362 .2638 .2756 .3346 .3425 .4016 .4252 .4724 .4921 .5512 .5709 .6102 .6496 .6890 .7283 .7677 .8071 .8268 .8661  .9449  .9843 1.0433 1.1024 1.1614 1.2205 1.2598 1.2992 1.3780 1.4173

starrett.com

D ecimal equivalents

Inch/Metric Tap Drill Sizes & Decimal Equivalents Drill Size

decimal EQUIV.

tap size

80 .0135 79 .0145 1 .0156 64 78 .0160 77 .0180 76 .0200 75 .0210 74 .0225 73 .0240 72 .0250 71 .0260 70 .0280 69 .0292 1 68 .0310 .0312 32 67 .0320 66 .0330 65 .0350 64 .0360 63 .0370 62 .0380 61 .0390 60 .0400 59 .0410 58 .0420 57 .0430 56 .0465 3 .0469 0 - 80 64 55 .0520 54 .0550 1 53 .0595 1 - 64, 72 .0625 16 52 .0635 51 .0670 50 .0700 2 - 56, 64 49 .0730 48 .0760 5 .0781 64 47 .0785 3 - 48 46 .0810 45 .0820 3 - 56 44 .0860 43 .0890 4 - 40 3 42 .0935 4 - 48 .0938 32 41 .0960 40 .0980 39 .0995 38 .1015 5 - 40

Drill Size

decimal EQUIV.

37 .1040 36 .1065 7 .1094 64 35 .1100 34 .1110 33 .1130 32 .1160 31 .1200 1 8 30 .1250 .1285 29 .1360 28 .1405 9 .1406 64 27 .1440 26 .1470 25 .1495 24 .1520 5 23 .1540 32 22 .1562 .1570 21 .1590 20 .1610 19 .1660 18 .1695 11 .1719 64 17 .1730 16 .1770 15 .1800 14 .1820 3 13 .1850 16 12 .1875 .1890 11 .1910 10 .1935 9 .1960 8 .1990 7 .2010 13 .2031 64 6 .2040 5 .2055 4 .2090 7 3 .2130 32 2 .2188 .2210 1 .2280 .2340 A 15 .2344 64 B .2380 C .2420

tap size

Drill Size

5 - 44 6 - 32

1 D 4 E F G 17 64 H I J 9 K 32 L M 19 64 5 N 16 O P 21 64 Q 11 R 32 S T 23 64 U 3 8 V W 25 64 X 13 Y 32 Z 27 64 7 29 16 64 15 32 31 64 1 33 2 64 17 32 35 64 9 37 16 64

6 - 40

8 - 32, 36

10 - 24

10 - 32

12 - 24 12 - 28

1/4 -

20

1/4 -

28

decimal EQUIV.

.2460 .2500 .2570 .2610 .2656 .2660 .2720 .2770 .2810 .2812 .2900 .2950 .2969 .3020 .3125 .3160 .3230 .3281 .3320 .3390 .3438 .3480 .3580 .3594 .3680 .3750 .3770 .3860 .3906 .3970 .4040 .4062 .4130 .4219 .4375 .4531

tap size

5/16 -

18

5/16 -

24

3/8 -

16

3/8 -

24

7/16 -

14

7/16 -

20

1/2 -

13

1/2 -

20

.4688 .4844 9/16 - 12 .5000 .5156 9/16 - 18 .5312

5/8 -

11

.5469 .5625 .5781

5/8 -

18

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