Tap Drill Size Chart for Standard Threads
American Standard Thread
......
ISO Metric Thread
Thread Size
Tap Drill Size (in.)
Thread Size
Tap Drill Size(mm)
0-80
3/64
M1 x 0.25
0.75
1-64
53
M1.1 x 0.25
0.85
1-72
53
M1.2 x 0.25
0.95
2-56
51
M1.4 x 0.3
1.10
2-64
50
M1.6 x 0.35
1.25
3-48
5/64
M1.8 x 0.35
1.45
3-56
46
M2 x 0.4
1.60
4-40
43
M2.2 x 0.45
1.75
4-48
42
M2.5 x 0.45
2.05
5-40
39
M3 x 0.5
2.50
Thread Size
Tap Drill Size (in.)
......
Thread Size
Tap Drill Size(mm)
5-44
37
M3.5 x 0.6
2.90
6-32
36
M4 x 0.7
3.30
6-40
33
M4.5 x 0.75
3.70
8-32
29
M5 x 0.8
4.20
8-36
29
M6 x 1
5.00
10-24
25
M7 x 1
6.00
10-32
21
M8 x 1.25
6.80
12-24
17
M9 x 1.25
7.80
12-28
15
M10 x 1.5
8.50
1/4-20
7
M11 x 1.5
9.50
Thread Size
Tap Drill Size (in.)
......
Thread Size
Tap Drill Size(mm)
1/4-28
3
M12 x 1.75
10.20
5/16-18
F
M14 x 2
12.00
5/16-24
I
M16 x 2
14.00
3/8-16
5/16
M18 x 2.5
15.50
3/8-24
Q
M20 x 2.5
17.50
7/16-14
U
M22 x 2.5
19.50
7/16-20
W
M24 x 3
21.00
1/2-13
27/64
M27 x 3
24.00
1/2-20
29/64
M30 x 3.5
26.50
9/16-12
31/64
M33 x 3.5
29.50
Thread Size
Tap Drill Size (in.)
......
Thread Size
Tap Drill Size(mm)
9/16-18
33/64
M36 x 4
32.00
5/8-11
17/32
M39 x 4
35.00
5/8-18
37/64
M42 x 4.5
37.50
3/4-10
21/32
M45 x 4.5
40.50
3/4-16
11/16
M48 x 5
43.00
7/8-9
49/64
M52 x 5
47.00
7/8-14
13/16
M56 x 5.5
50.50
1"-8
7/8
M60 x 5.5
54.50
1"-14
15/18
M64 x 6
58.00
M68 x 6
62.00
