Clearance Hole Drill Chart
The chart below displays a variety of common screw sizes and their clearance hole recommendations. The table provides two different class of
fits, Close Fit and Free Fit.
Each number or diameter of screw size has its own Close Fit or Free Fit, independent of threads per inch. Each fit is toleranced so that a
threaded object can pass through the hole while the head of the object will not. Free fit has a larger allowance while Close Fit has a tighter
allowance.
Screw Size
Close Fit
No. or Diameter
Diameter
Equivalent
000
00
0
1
2
3
4
5
6
8
10
12
1/4
5/16
3/8
7/16
1/2
9/16
5/8
11/16
3/4
13/16
7/8
15/16
1
0.0340
0.0440
0.0600
0.0730
0.0860
0.0990
0.1120
0.1250
0.1380
0.1640
0.1900
0.2160
0.2500
0.3125
0.3750
0.4375
0.5000
0.5625
0.6250
0.6875
0.7500
0.8125
0.8750
0.9375
1.0000
Free Fit
Drill Size
Decimal
Equivalent
Drill Size
Decimal
Equivalent
65
3/64
52
48
43
37
32
30
27
18
9
2
F
P
W
29/64
33/64
37/64
41/64
45/64
49/64
53/64
57/64
61/64
1-1/64
0.0350
0.0469
0.0635
0.0760
0.0890
0.1040
0.1160
0.1285
0.1440
0.1695
0.1960
0.2210
0.2570
0.3230
0.3860
0.4531
0.5156
0.5781
0.6406
0.7031
0.7656
0.8281
0.8906
0.9531
1.0156
62
55
50
46
41
35
30
29
25
16
7
1
H
Q
X
15/32
17/32
19/32
21/32
23/32
25/32
27/32
29/32
31/32
1-1/32
0.0380
0.0520
0.0700
0.0810
0.0960
0.1100
0.1285
0.1360
0.1495
0.1770
0.2010
0.2280
0.2660
0.3320
0.3970
0.4687
0.5312
0.5938
0.6562
0.7188
0.7812
0.8438
0.9062
0.9688
1.0313