PROTO, Industrial Tools

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Conversion Charts


Decimal Equivalents of Millimeter, Fractional and Number Drill Sizes
Millimeter
Dec. Equiv.
Fractional
Drill Size
Number
.1
.0039
 
 
.15
.0059
 
 
.2
.0079
 
 
.25
.0098
 
 
.3
.0118
 
 
....
.0135
 
80
.35
.0138
 
 
....
.0145
 
79
.39
.0156
1/64
..
.4
.0157
 
 
....
.0160
 
78
.45
.0177
 
 
....
.0180
 
77
.5
.0197
 
 
....
.0200
 
76
....
.0210
 
75
.55
.0217
 
 
....
.0225
 
74
.6
.0236
 
 
....
.0240
 
73
....
.0250
 
72
.65
.0256
 
 
....
.0260
 
71
....
.0280
 
70
.7
.0286
 
 
....
.0292
 
69
.75
.0295
 
 
....
.0310
 
68
.79
.0312
1/32
..
.8
.0315
 
 
....
.0320
 
67
....
.0330
 
66
.85
.0335
 
 
....
.0350
 
65
.9
.0354
 
 
....
.0360
 
64
....
.0370
 
63
.95
.0374
 
 
....
.0380
 
62
....
.0390
 
61
1.0
.0394
 
 
....
.0400
 
60
....
.0410
 
59
1.05
.0413
 
 
....
.0420
 
58
....
.0430
 
57
1.1
.0433
 
 
1.15
.0452
 
 
....
.0465
 
56
1.19
.0469
3/64
..
1.2
.0472
 
 
1.25
.0492
 
 
1.3
.0512
 
 
....
.0520
 
55
1.35
.0531
 
 
....
.0550
 
54
1.4
.0551
 
 
1.45
.0570
 
 
1.5
.0591
 
 
....
.0595
 
53
1.55
.0610
 
 
1.59
.0625
1/16
 
1.6
.0629
 
 
....
.0635
 
52
1.65
.0649
 
 
1.7
.0669
 
 
....
.0670
 
51
1.75
.0689
 
 
....
.0700
 
50
1.8
.0709
 
 
1.85
.0728
 
 
....
.0730
 
49
1.9
.0748
 
 
....
.0760
 
48
1.95
.0767
 
 
1.98
.0781
5/64
..
....
.0785
 
47
2.0
.0787
 
 
2.05
.0807
 
 
....
.0810
 
46
....
.0820
 
45
2.1
.0827
 
 
2.15
.0846
 
 
....
.0860
 
44
2.2
.0866
 
 
2.25
.0885
 
 
....
.0890
 
43
2.3
.0905
 
 
2.35
.0925
 
 
....
.0935
 
42
2.38
.0937
3/32
..
2.4
.0945
 
 
....
.0960
 
41
2.45
.0964
 
 
....
.0980
 
40
2.5
.0984
 
 
....
.0995
 
39
....
.1015
 
38
2.6
.1024
 
 
....
.1040
 
37
2.7
.1063
 
 
....
.1065
 
36
2.75
.1082
 
 
2.78
.1094
7/64
..
....
.1100
 
35
2.8
.1102
 
 
....
.1110
 
34
....
.1130
 
33
2.9
.1141
 
 
....
.1160
 
32
3.0
.1181
 
 
....
.1200
 
31
3.1
.1220
 
 
3.18
.1250
1/8
..
3.2
.1260
 
 
3.25.
.1279
 
 
....
.1285
 
30
3.3
.1299
 
 
3.4.
.1338
 
 
....
.1360
 
29
3.5
.1378
 
 
....
.1405
 
28
3.57
.1406
9/64
..
3.6
.1417
 
 
....
.1440
 
27
3.7
.1457
 
 
....
.1470
 
26
3.75
.1476
 
 
....
.1495
 
25
3.8
.1496
 
 
....
.1520
 
24
3.9
.1535
 
 
....
.1540
 
23
3.97
.1562
5/32
..
....
.1570
 
22
4.0
.1575
 
 
....
.1590
 
21
....
.1610
 
20
4.1
.1614
 
 
4.2
.1654
 
 
....
.1660
 
19
4.25
.1673
 
 
4.3
.1693
 
 
....
.1695
 
18
4.37
.1719
11/64
..
....
.1730
 
17
4.4
.1732
 
 
....
.1770
 
16
4.5
.1771
 
 
....
.1800
 
15
4.6
.1811
 
 
....
.1820
 
14
4.7
.1850
 
13
4.75
.1870
 
 
4.76
.1875
3/16
..
4.8
.1890
 
12
....
.1910
 
11
4.9
.1929
 
 
....
.1935
 
10
....
.1960
 
9
5.0
.1968
 
 
....
.1990
 
8
5.1
.2008
 
 
....
.2010
 
7
5.16
.2031
13/64
..
....
.2040
 
6
5.2
.2047
 
 
....
.2055
 
5
5.25
.2067
 
 
5.3
.2086
 
 
....
.2090
 
4
5.4
.2126
 
 
....
.2130
 
3
5.5
.2165
 
 
5.56
.2187
7/32
..
5.6
.2205
 
 
....
.2210
 
2
5.7
.2244
 
 
5.75
.2263
 
 
....
.2280
 
1
5.8
.2283
 
 
5.9
.2323
 
 
....
.2340
 
A
5.95
.2344
15/64
..
6.0
.2362
 
 
....
.2380
 
B
6.1
.2401
 
 
....
.2420
 
C
6.2
.2441
 
 
6.25
.2460
 
D
6.3
.2480
 
 
6.35
.2500
1/4
E
6.4
.2520
 
 
6.5
.2559
 
 
....
.2570
 
F
6.6
.2598
 
 
....
.2610
 
G
6.7
.2638
 
 
6.75
.2656
17/64
..
6.75
.2657
 
 
....
.2660
 
H
6.8
.2677
 
 
6.9
.2716
 
 
....
.2720
 
I
7.0
.2756
 
 
....
.2770
 
J
7.1
.2795
 
 
....
.2811
 
K
7.14
.2812
9/32
..
7.2
.2835
 
 
7.25
.2854
 
 
7.3
.2874
 
 
....
.2900
 
L
7.4
.2913
 
 
....
.2950
 
M
7.5
.2953
 
 
7.54
.2968
19/64
..
7.6
.2992
 
 
....
.3020
 
N
7.7
.3031
 
 
7.75
.3051
 
 
7.8
.3071
 
 
7.9
.3110
 
 
7.94
.3125
5/16
..
8.0
.3150
 
 
....
.3160
 
O
8.1
.3189
 
 
8.2
.3228
 
 
....
.3230
 
P
8.25
.3248
 
 
8.3
.3268
 
 
8.33
.3281
21/64
..
8.4
.3307
 
 
....
.3320
 
Q
8.5
.3346
 
 
8.6
.3386
 
 
....
.3390
 
R
8.7
.3425
 
 
8.73
.3437
11/32
 
8.75
.3445
 
 
8.8
.3465
 
 
....
.3480
 
S
8.9
.3504
 
 
9.0
.3543
 
 
....
.3580
 
T
9.1
.3583
 
 
9.13
.3594
23/64
..
9.2
.3622
 
 
9.25
.3641
 
 
9.3
.3661
 
 
....
.3680
 
U
9.4
.3701
 
 
9.5
.3740
 
 
9.53
.3750
3/8
..
....
.3770
 
V
9.6
.3780
 
 
9.7
.3819
 
 
9.75
.3838
 
 
9.8
.3858
 
 
....
.3860
 
W
9.9
.3898
 
 
9.92
.3906
25/64
..
10.0
.3937
 
 
....
.3970
 
X
....
.4040
 
Y
10.32
.4062
13/32
..
....
.4130
 
Z
10.5
.4134
 
 
10.72
.4219
27/64
 
11.0
.4330
 
 
11.11
.4375
7/16
 
11.5
.4528
 
 
11.51
.4531
29/64
 
11.91
.4687
15/32
 
12.0
.4724
 
 
12.30
.4843
31/64
 
12.5
.4921
 
 
12.7
.5000
1/2
 
13.0
.5118
 
 
13.10
.5156
33/64
 
13.49
.5312
17/32
 
13.5
.5315
 
 
13.89
.5469
35/64
 
14.0
.5512
 
 
14.29
.5625
9/16
 
14.5
.5709
 
 
14.68
.5781
37/64
 
15.0
.5906
 
 
15.08
.5937
19/32
 
15.48
.6094
39/64
 
15.5
.6102
 
 
15.88
.6250
5/8
 
16.0
.6299
 
 
16.27
.6406
41/64
 
16.5
.6496
 
 
16.67
.6562
21/32
 
17.0
.6693
 
 
17.06
.6719
43/64
 
17.46
.6875
11/16
 
17.5
.6890
 
 
17.86
.7031
45/64
 
18.0
.7087
 
 
18.26
.7187
23/32
 
18.5
.7283
 
 
18.65
.7344
47/64
 
19.0
.7480
 
 
19.05
.7500
3/4
 
19.45
.7656
49/64
 
19.5
.7677
 
 
19.84
.7812
25/32
 
20.0
.7874
 
 
20.24
.7969
51/64
 
20.5
.8071
 
 
20.64
.8125
13/16
 
21.0
.8268
 
 
21.03
.8281
53/64
 
21.43
.8437
27/32
 
21.5
.8465
 
 
21.83
.8594
55/64
 
22.0
.8661
 
 
22.23
.8750
7/8
 
22.5
.8858
 
 
22.62
.8906
57/64
 
23.0
.9055
 
 
23.02
.9062
29/32
 
23.42
.9219
59/64
 
23.5
.9252
 
 
23.81
.9375
15/16
 
24.0
.9449
 
 
24.21
.9531
61/64
 
24.5
.9646
 
 
24.61
.9687
31/32
 
25.0
.9843
 
 
25.03
.9844
63/64
 
25.4
1.0000
1