Drill Size Decimal eQUiValeNT Tap Size

1939 32 .593864 5 .609441 8 .625064 21 .640643 32 .6562 3/4 - 1064 11 .671945 16 .6875 3/4 - 1664 23 .703147 32 .718864 3 .734449 4 .750064 25 .7656 7/8 - 951 32 .781264 13 .796953 16 .8125 7/8 - 1464 27 .828155 32 .843864 7 .859457 8 .8750 1 - 864 29 .890659 32 .906264 15 .9219 1 - 1261 16 .9375 1 - 1464 31 .953163 32 .968864 .9844 11/8 - 7

1 1.000013/64 1.0469 11/8 - 1217/64 1.1094 11/4 - 7

11/8 1.1250111/64 1.1719 11/4 - 12

17/32 1.2188 13/8 - 611/4 1.2500

119/64 1.2969 13/8 - 12111/32 1.3438 11/2 - 6

13/8 1.3750127/64 1.4219 11/2 - 12

11/2 1.5000pipe ThreaD SizeS (NpSc)

ThreaD Drill ThreaD Drill1/8 – 27 11/32 11/2 – 111/2 13/41/4 – 18 7/16 2 – 111/2 27/323/8 – 18 37/64 21/2 – 8 221/321/2 – 14 23/32 3 – 8 31/43/4 – 14 59/64 31/2 – 8 33/41 – 111/2 15/32 4 – 8 41/4

11/4 – 111/2 11/2

meTric Tap Drill SizeSmeTric Tap Tap Drill (mm) Decimal (inch)

m1.6 x 0.35 1.25 .0492m1.8 x 0.35 1.45 .0571m2 x 0.4 1.60 .0630m2.2 x 0.45 1.75 .0689m2.5 x 0.45 2.05 .0807m3 x 0.5 2.50 .0984m3.5 x 0.6 2.90 .1142m4 x 0.7 3.30 .1299m4.5 x 0.75 3.70 .1457m5 x 0.8 4.20 .1654m6 x 1 5.00 .1968m7 x 1 6.00 .2362m8 x 1.25 6.70 .2638m8 x 1 7.00 .2756m10 x 1.5 8.50 .3346m10 x 1.25 8.70 .3425m12 x 1.75 10.20 .4016m12 x 1.25 10.80 .4252m14 x 2 12.00 .4724m14 x 1.5 12.50 .4921m16 x 2 14.00 .5512m16 x 1.5 14.50 .5709m18 x 2.5 15.50 .6102m18 x 1.5 16.50 .6496m20 x 2.5 17.50 .6890m20 x 1.5 18.50 .7283m22 x 2.5 19.50 .7677m22 x 1.5 20.50 .8071m24 x 3 21.00 .8268m24 x 2 22.00 .8661m27 x 3 24.00 .9449m27 x 2 25.00 .9843m30 x 3.5 26.50 1.0433m30 x 2 28.00 1.1024m33 x 3.5 29.50 1.1614m33 x 2 31.00 1.2205m36 x 4 32.00 1.2598m36 x 3 33.00 1.2992m39 x 4 35.00 1.3780m39 x 3 36.00 1.4173

Decimalequivalents

Bulletin 1317-150M/S 06/09 starrett.com

Inch/MetrIc tap DrIll SIzeS & DecIMal equIvalentS

Decimalequivalents

Drill Size Decimal eQUiV. Tap Size

80 .01351 79 .014564 .0156

78 .016077 .018076 .020075 .021074 .022573 .024072 .025071 .026070 .028069 .0292

1 68 .031032 .0312

67 .032066 .033065 .035064 .036063 .037062 .038061 .039060 .040059 .041058 .042057 .0430

3 56 .046564 .0469 0 - 80

55 .052054 .0550

1 53 .0595 1 - 64, 7216 .0625

52 .063551 .067050 .0700 2 - 56, 6449 .0730

5 48 .076064 .0781

47 .0785 3 - 4846 .081045 .0820 3 - 5644 .086043 .0890 4 - 40

3 42 .0935 4 - 4832 .0938

41 .096040 .098039 .099538 .1015 5 - 40

Drill Size Decimal eQUiV. Tap Size

37 .1040 5 - 447 36 .1065 6 - 3264 .1094

35 .110034 .111033 .1130 6 - 4032 .1160

1 31 .12008 .1250

30 .128529 .1360 8 - 32, 36

9 28 .140564 .1406

27 .144026 .147025 .1495 10 - 2424 .1520

5 23 .154032 .1562

22 .157021 .1590 10 - 3220 .161019 .1660

11 18 .169564 .1719

17 .173016 .1770 12 - 2415 .180014 .1820 12 - 28

3 13 .185016 .1875

12 .189011 .191010 .19359 .19608 .1990

13 7 .2010 1/4 - 2064 .2031

6 .20405 .20554 .2090

7 3 .2130 1/4 - 2832 .2188

2 .22101 .2280

15 a .234064 .2344

B .2380c .2420

Drill Size Decimal eQUiV. Tap Size

1 D .24604 e .2500

F .2570 5/16 - 1817 G .261064 .2656

h .2660i .2720 5/16 - 24J .2770

9 K .281032 .2812

l .290019 m .295064 .2969

5 N .302016 .3125 3/8 - 16

O .316021 p .323064 .3281

Q .3320 3/8 - 2411 r .339032 .3438

S .348023 T .358064 .3594

3 U .3680 7/16 - 148 .3750

V .377025 W .386064 .3906 7/16 - 20

X .397013 Y .404032 .4062

27 z .413064 7 .4219 1/2 - 1329 16 .437564 .4531 1/2 - 20

1532 .4688

3164 1 .4844 9/16 - 1233 2 .500064 .5156 9/16 - 18

1732 .5312 5/8 - 11

3564 9 .546937 16 .562564 .5781 5/8 - 18

The L.S. Starrett Company — World’s Greatest Toolmakers

Inch/MetrIc tap DrIll SIzeS & DecIMal equIvalentS