Charts

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Metric Thread Cut Tap Drill Sizes Chart

MetricThreadsChart.pdf

METRIC THREAD CUT TAP DRILL SIZES
Tap / Thread Size* Basic Major    Diameter Tap Drill Size**
M1.6 x 0.35 0.063 1.25mm or #55
M2 x 0.4 0.0787 1.60mm or #52
M2.5 x 0.45 0.0984 2.05mm or #46
M3 x 0.5 0.1181 2.50mm or #39
M3.5 x 0.6 0.1378 2.90mm or #32
M4 x 0.7 0.1575 3.30mm or #30
M5 x 0.8 0.1969 4.20mm or #19
M6 x 1 0.2362 5.00mm or #8
M8 x 1.25 0.315 6.80mm or H
M8 x 1 0.315 7.00mm or J
M10 x 1.5 0.3937 8.50mm or R
M10 x 1.25 0.3937 8.80mm or 11/32
M12 x 1.75 0.4724 10.20mm or 13/32
M12 x 1.25 0.4724 10.80mm or 27/64
M14 x 2 0.5512 12.00mm or 15/32
M14 x 1.5 0.5512 12.50mm or 1/2
M16 x 2 0.6299 14.00mm or 35/64
M16 x 1.5 0.6299 14.50mm or 37/64
M18 x 2.5 0.7087 15.50mm or 39/64
M18 x 1.5 0.7087 16.50mm or 21/32
M20 x 2.5 0.7874 17.50mm or 11/16
M20 x 1.5 0.7874 18.50mm or 47/64
M22 x 2.5 0.8661 19.50mm or 49/64
M22 x 1.5 0.8661 20.50mm or 13/16
M24 x 3 0.9449 21.00mm or 53/64
M24 x 2 0.9449 22.00mm or 7/8
M27 x 3 1.063 24.00mm or 15/16
M27 x 2 1.063 25.00mm or 1

*Coarse series shown in red.
** Closest size for 75% theoretical thread. 

Metric Drill Sizes

MetricDrillSizesChart.pdf

Drill Decimal Drill Decimal Drill Decimal Drill Decimal
.38mm .0150 2.55mm .1004 6.25mm .2461 10.20mm .4016
.40mm .0157 2.60mm .1024 6.30mm .2480 10.50mm .4134
.42mm .0165 2.65mm .1043 6.40mm .2520 10.80mm .4252
.45mm .0177 2.70mm .1063 6.50mm .2559 11.00mm .4331
.48mm .0189 2.75mm .1083 6.60mm .2598 11.20mm .4409
.50mm .0197 2.80mm .1102 6.70mm .2638 11.50mm .4528
.55mm .0217 2.90mm .1142 6.75mm .2657 11.80mm .4646
.60mm .0236 3.00mm .1181 6.80mm .2677 12.00mm .4724
.65mm .0256 3.10mm .1220 6.90mm .2717 12.20mm .4803
.70mm .0276 3.20mm .1260 7.00mm .2756 12.50mm .4921
.75mm .0295 3.25mm .1280 7.10mm .2795 13.00mm .5118
.80mm .0315 3.30mm .1299 7.20mm .2835 13.50mm .5315
.85mm .0335 3.40mm .1339 7.25mm .2854 14.00mm .5512
.90mm .0354 3.50mm .1378 7.30mm .2874 14.50mm .5709
.95mm .0374 3.60mm .1417 7.40mm .2913 15.00mm .5906
1.00mm .0394 3.70mm .1457 7.50mm .2953 15.50mm .6102
1.05mm .0413 3.75mm .1476 7.60mm .2992 16.00mm .6299
1.10mm .0433 3.80mm .1496 7.70mm .3031 16.50mm .6496
1.15mm .0453 3.90mm .1535 7.75mm .3051 17.00mm .6693
1.20mm .0472 4.00mm .1575 7.80mm .3071 17.50mm .6890
1.25mm .0492 4.10mm .1614 7.90mm .3110 18.00mm .7087
1.30mm .0512 4.20mm .1654 8.00mm .3150 18.50mm .7283
1.35mm .0531 4.25mm .1673 8.10mm .3189 19.00mm .7480
1.40mm .0551 4.30mm .1693 8.20mm .3228 19.50mm .7677
1.45mm .0571 4.40mm .1732 8.25mm .3248 20.00mm .7874
1.50mm .0591 4.50mm .1772 8.30mm .3268 20.50mm .8071
1.55mm .0610 4.60mm .1811 8.40mm .3307 21.00mm .8268
1.60mm .0630 4.70mm .1850 8.50mm .3346 21.50mm .8465
1.65mm .0650 4.75mm .1870 8.60mm .3386 22.00mm .8661
1.70mm .0669 4.80mm .1890 8.70mm .3425 22.50mm .8858
1.75mm .0689 4.90mm .1929 8.75mm .3445 23.00mm .9055
1.80mm .0709 5.00mm .1969 8.80mm .3465 23.50mm .9252
1.85mm .0728 5.10mm .2008 8.90mm .3504 24.00mm .9449
1.90mm .0748 5.20mm .2047 9.00mm .3543 24.50mm .9646
1.95mm .0768 5.25mm .2067 9.10mm .3583 25.00mm .9843
2.00mm .0787 5.30mm .2087 9.20mm .3622
2.05mm .0807 5.40mm .2126 9.25mm .3642
2.10mm .0827 5.50mm .2165 9.30mm .3661
2.15mm .0846 5.60mm .2205 9.40mm .3701
2.20mm .0866 5.70mm .2244 9.50mm .3740
2.25mm .0886 5.75mm .2264 9.60mm .3780
2.30mm .0906 5.80mm .2283 9.70mm .3819
2.35mm .0925 5.90mm .2323 9.75mm .3839
2.40mm .0945 6.00mm .2362 9.80mm .3858
2.45mm .0965 6.10mm .2402 9.90mm .3898

Tap Drill Sizes

TapDrillSizesChart.pdf

TAP DRILL SIZES FOR CUT AND FORMED THREADS
TAP     SIZE TAP DRILL SIZE
Cut Thread Formed Thread
0-80 3/64 .0469 54 .0545
1-64 53 .0595 1.65 mm .065
1-72 53 ,0595 1.7 mm .0669
2-56 50 .0700 5/64 .0781
2-64 50 .0700 2 mm .0787
3-48 46 .0810 43 .089
3-56 45 .0820 2.3 mm .0906
4-40 43 .0890 39 .0995
4-48 3/32 .0938 2.6 mm .1024
5-40 38 .1015 33 .113
5-44 37 .1040 2.9 mm .1142
6-32 34 .1110 1/8 .125
6-40 32 .1160 3.2 mm .1260
8-32 29 .1360 25 .1495
8-36 29 .1360 24 .1520
10-24 23 .1540 11/64 .1719
10-32 20 .1610 16 .1770
12-24 15 .1800 5 mm .1968
12-28 13 .1850 8 .1990
1/4-20 13/64 .2031 1 .2280
1/4-28 7/32 .2187 A .2340
5/16-18 G .2610 7.3 mm .2874
5/16-24 J .2770 M .2950
3/8-16 O .3160 S .3480
3/8-24 R .3390 T .358
7/16-14 U .3680 13/32 .406
7/16-20 25/64 .3906 10.5 mm .4134
1/2-13 27/64 .4219 * .466
1/2-20 29/64 .4531 * .478
9/16-12 31/64 .4844 * .525
9/16-18 33/64 .5156 * ,538
5/8-11 35/64 .5469 * .584
5/8-18 37/64 .5781 * .600
11/16-11 39/64 .6094 * .646
11/16-16 5/8 .6250 * .660
3/4-10 21/32 .6562 45/64 .7031
3/4-16 11/16 .6875 * .722
7/8-9 49/64
7/8-14 13/16
1-8 7/8
1-4 15/16
1-1/8-7 63/64
1-1/8-12 1-3/64

CUT TAP NOTE: At times, you can drill a slightly larger hole to make the tapping process a bit easier. This can be done without sacrificing much of the thread’s strength. This is because most of a thread’s strength is found at its base. By making the hole larger, you are essentially cutting off the tip of a thread, not its base. You are also lowering the amount of resistance encountered while cutting the thread. This is a trick that some machinists use when they are concerned about breaking a tap tool in a hole, lowering the horsepower (HP) requirement for a self-reversing tap head or automatic tapping machine such as a Control Feed Tapper or Lead Screw tap machine.