Recommended Tapping Drill Size

ISO Metric Coarse

Size (mm) Pitch (mm) Drill (mm)
M1 .25 .75
M1.1 .25 .85
M1.2 .25 .95
M1.4 .3 1.1
M1.6 .35 1.25
M1.8 .35 1.45
M2 .4 1.6
M2.2 .45 1.75
M2.5 .45 2.05
M3 .5 2.5
M3.5 .6 2.9
M4 .7 3.3
M4.5 .75 3.75
M5 .8 4.2
M6 1 5
M7 1 6
M8 1.25 6.75
M9 1.25 7.75
M10 1.5 8.5
M11 1.5 9.5
M12 1.75 10.2
M14 2 12
M16 2 14
M18 2.5 15.5
M20 2.5 17.5
M22 2.5 19.5
M24 3 21
M27 3 24
M30 3.5 26.5
M33 3.5 29.5
M36 4 32
M39 4 35
M42 4.5 37.5
M45 4.5 40.5
M48 5 43
M52 5 47
M56 5.5 50.5
M60 5.5 54.5
M64 6 58
M68 6 62
M72 6 66
M76 6 70

UNC

Size No.
or inch
Pitch
TPI
Drill (mm)
#1 64 1.55
#2 56 1.85
#3 48 2.1
#4 40 2.35
#5 40 2.65
#6 32 2.85
#8 32 3.5
#10 24 3.9
#12 24 4.5
1/4 20 5.1
5/16 18 6.6
3/8 16 8
7/16 14 9.4
1/2 13 10.8
9/16 12 12.2
5/8 11 13.5
3/4 10 16.5
7/8 9 19.5
1 8 22.25
1 1/8 7 25
1 1/4 7 28
1 3/8 6 30.75
1 1/2 6 34
1 3/4 5 39.5
2 4.5 45
2 1/4 4.5 51.5
2 1/2 4 57.25
2 3/4 4 63.5
3 4 70

UNF

Size No.
or inch
Pitch
TPI
Drill (mm)
#0 80 1.25
#1 72 1.55
#2 64 1.9
#3 56 2.15
#4 48 2.4
#5 44 2.7
#6 40 2.95
#8 36 3.5
#10 32 4.1
#12 28 4.7
1/4 28 5.5
5/16 24 6.9
3/8 24 8.5
7/16 20 9.9
1/2 20 11.5
9/16 18 12.9
5/8 18 14.5
3/4 16 17.5
7/8 14 20.4
1 12 23.25
1 1/8 12 26.5
1 1/4 12 29.5
1 3/8 12 32.75
1 1/2 12 36

 

ISO Metric Fine

Size (mm) Pitch (mm) Drill (mm)
M2 .25 1.75
M2.2 .25 1.95
M2.3 .25 2.05
M2.5 .35 2.15
M2.6 .35 2.25
M3 .35 2.65
M3.5 .35 3.15
M4 .35 3.65
M4 .5 3.5
M5 .35 4.65
M5 .5 4.5
M5 .75 4.25
M5.5 .5 5
M6 .5 5.5
M6 .75 5.25
M7 .75 6.25
M8 .5 7.5
M8 .75 7.25
M8 1 7
M9 .75 8.25
M9 1 8
M10 .5 9.5
M10 .75 9.25
M10 1 9
M10 1.25 8.75
M11 .75 10.25
M11 1 10
M11 1.25 9.75
M12 .5 11.5
M12 .75 11.25
M12 1 11
M12 1.25 10.75
M12 1.5 10.5
M14 1 13
M14 1.25 12.75
M14 1.5 12.5
M15 .75 14.25
M15 1 14
M15 1.5 13.5
M16 .5 15.5
M16 .75 15.25
M16 1 15
M16 1.25 14.75
M16 1.5 14.5
M17 1 16
M17 1.5 15.5
M18 .75 17.25
M18 1 17
M18 1.25 16.75
M18 1.5 16.5
M18 2 16
M19 1 18
M20 1 19
M20 1.5 18.5
M20 2 18
M22 1 21
M22 1.5 20.5
M22 2 20
M24 1 23
M24 1.5 22.5
M24 2 22
M25 1 24
M25 1.5 23.5
M25 2 23
M27 1 26
M27 1.5 25.5
M27 2 25
M28 1 27
M28 1.5 26.5
M28 2 26
M30 1 29
M30 1.5 28.5
M30 2 28
M30 3 27
M32 1 31
M32 1.5 30.5
M32 2 30
M33 1.5 31.5
M33 2 31
M33 3 30
M35 1.5 33.5
M35 2 33
M35 3 32
M36 1 35
M36 1.5 34.4
M36 2 34
M36 3 33
M38 1 37
M38 1.5 36.5
M38 2 36
M39 1.5 37.5
M39 2 37
M39 3 36
M40 1 39
M40 1.5 38.5
M40 3 37
M42 1.5 40.5
M42 2 40
M42 3 39
M42 4 38
M45 1.5 43.5
M45 2 43
M45 3 42
M48 1.5 46.5
M48 2 46
M48 3 45
M48 4 44
M50 1.5 48.5
M50 2 48
M50 3 47
M52 1.5 50.5
M52 2 50
M52 3 49
M52 4 48
M56 2 54
M56 4 52

*All information is strictly informative