Pilot Hole Data

Pilot Hole and Shank Clearance Hole Boring Recommendations for Wood Screws
Screw
Diameter
Bit or Drill Sizes

No of Auger Bit

To Counterbore for striking head

For Shank Clearance Holes For Pilot Holes
Hard Woods Soft Woods
Twist Bit
Nearest Size in fractions of an inch
Drill
Gauge No or letter to be used for maximum holding power
Twist Bit
Nearest Size in fractions of an inch
Drill
Gauge No to be used for maximum
holding power
Twist Bit
Nearest Size in fractions
of an inch
Drill
Gauge No to be used for maximum
holding power
0 1/16 52 1/32 66 1/54 75 -
1 5/64 47 - 57 1/32 71 -
2 3/32 42 - 54 1/32 65 3
3 7/54 37 1/16 53 3/64 58 4
4 7/54 32 1/16 51 3/64 55 4
5 1/8 30 5/64 47 1/16 53 4
6 9/64 27 - 44 1/16 52 5
7 5/32 22 - 39 1/16 51 5
8 11/64 18 7/64 35 5/64 48 6
9 3/16 14 7/64 33 5/64 45 6
10 3/16 10 1/8 31 3/32 43 6
11 13/64 4 - 29 3/32 40 7
12 7/32 2 - 25 7/64 38 7
14 1/4 0 3/16 14 7/64 32 8
16 17/64 1 - 10 9/64 29 9
18 19/64 N 13/64 6 9/64 26 10
20 21/64 P 7/32 3 11/64 19 11
24 3/8 V 1/4 D 3/16 15 12
 
Self Tapping Screws - Hole Size Recommendations
Screw
Diameter
Thickness of Metal Pierced Hole Drilled or clean Punched Hole Screw
Diameter
Thickness of metal Pierced Hole Drilled or clean Punched Hole
USS Gauge No Equivalent Hole Dia Hole Dia Drill Size USS Gauge No Equivalent Hole Dia Hole Dia Drill Size
4
.112
28
26
24
22
20
.0156
.0188
.0250
.0313
.0375
.086
.086
.093
.098
.100
.0860
.0860
.0935
.0935
.0980
44
44
42
42
40
8
.165
26
24
22
20
18
.0188
.0250
.0313
.0375
.0500
.137
.137
.137
.137
-
.1130
.1130
.1160
.1200
.1280
33
33
32
31
30
6
.138
28
26
24
22
20
.0156
.0188
.0250
.0313
.0375
.111
.111
.111
.111
.111
.0995
.0995
.0995
.1015
.1065
39
39
39
38
36
10
.191
26
24
22
20
18
.0188
.0250
.0313
.0375
.0500
.158
.158
.158
.158
.158
.1285
.1285
.1285
.1360
.1495

30
30
30
29
25
7
.115

28
26
24
22
20

18

.0156
.0188
.0250
.0313
.0345
.0500
.121
.121
.121
.121
.121
-
.1040
.1040
.1100
.1130
.1160
.1200
37
37
35
33
32
31
12
.218
24
22
20
18
.0250
.0313
.0375
.0500
-
.185
.185
.185
.1470
.1495
.1520
.1570
26
25
24
22
            14
.251
24
22
20
18
.0250
.0313
.0375
.0500
-
.212
.212
.212

.1800
.1890
.1910
.1960

 

15
12
11
9

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