In other words
As the name suggests, cutting taps produce threads by progressively cutting away the space between threads into which the fastener´s external threads will fit. Forming taps, by contrast, remove no material. Instead, they move or displace material inside the hole to build up the threads and dig into the grooves.
Metric | Drill diameters for tapping threads | ||
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M1-M64 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø mm | mm | ø mm | ø mm |
1 | 0.25 | 0.75 | 0.90 |
1.6 | 0.35 | 1.25 | 1.40 |
1.8 | 0.35 | 1.45 | 1.65 |
2 | 0.40 | 1.60 | 1.80 |
2.2 | 0.45 | 1.75 | 2.00 |
2.5 | 0.45 | 2.05 | 2.30 |
3 | 0.50 | 2.50 | 2.80 |
3.5 | 0.60 | 2.90 | 3.20 |
4 | 0.70 | 3.30 | 3.70 |
4.5 | 0.75 | 3.80 | 4.15 |
5 | 0.80 | 4.20 | 4.60 |
6 | 1.00 | 5.00 | 5.50 |
7 | 1.00 | 6.00 | 6.50 |
8 | 1.25 | 6.80 | 7.40 |
9 | 1.25 | 7.80 | 8.40 |
10 | 1.50 | 8.50 | 9.30 |
11 | 1.50 | 9.50 | 10.30 |
12 | 1.75 | 10.30 | 11.20 |
14 | 2.00 | 12.00 | 13.00 |
16 | 2.00 | 14.00 | 15.00 |
18 | 2.50 | 15.50 | 16.80 |
20 | 2.50 | 17.50 | 18.90 |
22 | 2.50 | 19.50 | 20.80 |
24 | 3.00 | 21.00 | 22.70 |
27 | 3.00 | 24.00 | |
30 | 3.50 | 26.50 | |
33 | 3.50 | 29.50 | |
36 | 4.00 | 32.00 | |
39 | 4.00 | 35.00 | |
42 | 4.50 | 37.50 | |
45 | 4.50 | 40.50 | |
48 | 5.00 | 43.00 | |
52 | 5.00 | 47.00 | |
56 | 5.50 | 50.50 | |
64 | 6.00 | 58.00 |
Metric Fine | Drill diameters for tapping threads | ||
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MF3-MF40 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø mm | mm | ø mm | ø mm |
3 | 0.35 | 2.65 | 2.85 |
3.5 | 0.35 | 3.20 | 3.35 |
4 | 0.50 | 3.50 | 3.80 |
5 | 0.50 | 4.50 | 4.80 |
5.5 | 0.50 | 5.00 | 5.25 |
6 | 0.75 | 5.30 | 5.70 |
7 | 0.75 | 6.30 | 6.65 |
8 | 0.75 | 7.30 | 7.70 |
8 | 1.00 | 7.00 | 7.50 |
9 | 1.00 | 8.00 | 8.50 |
10 | 1.00 | 9.00 | 9.50 |
10 | 1.25 | 8.80 | 9.40 |
11 | 1.00 | 10.00 | 10.50 |
12 | 1.00 | 11.00 | 11.50 |
12 | 1.25 | 10.80 | 11.40 |
12 | 1.50 | 10.50 | 11.30 |
14 | 1.00 | 13.00 | 13.50 |
14 | 1.25 | 12.80 | 13.40 |
14 | 1.50 | 12.50 | 13.30 |
15 | 1.00 | 14.00 | 14.50 |
15 | 1.50 | 13.50 | 14.30 |
16 | 1.00 | 15.00 | 15.50 |
16 | 1.50 | 14.50 | 15.30 |
18 | 1.00 | 17.00 | 17.50 |
18 | 1.50 | 16.50 | 17.30 |
18 | 2.00 | 16.00 | 17.00 |
20 | 1.00 | 19.00 | 19.50 |
20 | 1.50 | 18.50 | 19.30 |
20 | 2.00 | 18.00 | 19.00 |
22 | 1.00 | 21.00 | 21.50 |
22 | 1.50 | 20.50 | 21.30 |
22 | 2.00 | 20.00 | 21.00 |
24 | 1.00 | 23.00 | 23.50 |
24 | 1.50 | 22.50 | 23.30 |
24 | 2.00 | 22.00 | 23.00 |
25 | 1.00 | 24.00 | |
25 | 1.50 | 23.50 | |
25 | 2.00 | 23.00 | |
27 | 1.50 | 25.50 | |
27 | 2.00 | 25.00 | |
28 | 1.50 | 26.50 | |
28 | 2.00 | 26.00 | |
30 | 1.50 | 28.50 | |
30 | 2.00 | 28.00 | |
32 | 1.50 | 30.50 | |
32 | 2.00 | 30.00 | |
33 | 2.00 | 31.00 | |
35 | 1.50 | 33.50 | |
36 | 1.50 | 34.50 | |
36 | 2.00 | 34.00 | |
36 | 3.00 | 33.00 | |
38 | 1.50 | 36.50 | |
39 | 3.00 | 36.00 | |
40 | 1.50 | 38.50 | |
40 | 2.00 | 38.00 | |
40 | 3.00 | 37.00 |
Whitworth | Drill diameters for tapping threads | ||
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BSW 3/32 - 2 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø | TPI | ø mm | ø mm |
3/32 | 48 | 1.85 | 2.10 |
1/8 | 40 | 2.55 | 2.90 |
5/32 | 32 | 3.20 | 3.60 |
3/16 | 24 | 3.70 | 4.30 |
7/32 | 24 | 4.50 | |
1/4 | 20 | 5.10 | 5.80 |
5/16 | 18 | 6.50 | 7.30 |
3/8 | 16 | 7.90 | 8.80 |
7/16 | 14 | 9.20 | 10.20 |
1/2 | 12 | 10.50 | 11.60 |
9/16 | 12 | 12.00 | 13.20 |
5/8 | 11 | 13.50 | 14.70 |
3/4 | 10 | 16.50 | 17.70 |
7/8 | 9 | 19.25 | 20.75 |
1 | 8 | 22.00 | 23.75 |
1.1/8 | 7 | 24.75 | |
1.1/4 | 7 | 28.00 | |
1.3/8 | 6 | 30.50 | |
1.1/2 | 6 | 33.50 | |
1.5/8 | 5 | 35.50 | |
1.3/4 | 5 | 39.00 | |
1.7/8 | 4.1/2 | 41.50 | |
2 | 4.1/2 | 41.50 |
BSP | Drill diameters for tapping threads | ||
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BSP 1/8 - 3 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø | TPI | ø mm | ø mm |
1/8 | 28 | 8.80 | 9.30 |
1/4 | 19 | 11.80 | 12.50 |
3/8 | 19 | 15.25 | 16.00 |
1/2 | 14 | 19.00 | 20.00 |
5/8 | 14 | 21.00 | 22.00 |
3/4 | 14 | 24.50 | 25.50 |
7/8 | 14 | 28.25 | 29.30 |
1 | 11 | 30.75 | 32.00 |
1.1/4 | 11 | 39.50 | |
1.1/2 | 11 | 45.00 | |
1.3/4 | 11 | 51.00 | |
2 | 11 | 57.00 | |
2.1/4 | 11 | 63.00 | |
2.1/2 | 11 | 72.50 | |
2.3/4 | 11 | 79.00 | |
3 | 11 | 85.50 |
Drill diameters for tapping threads | |||
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UNC No.2 - No.12 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø mm | mm | ø mm | ø mm |
No.2 | 56 | 1.85 | 2.00 |
No.3 | 48 | 2.10 | 2.30 |
No.4 | 40 | 2.35 | 2.60 |
No.5 | 40 | 2.65 | 2.90 |
No.6 | 32 | 2.85 | 3.20 |
No.8 | 32 | 3.50 | 3.80 |
No.10 | 24 | 3.90 | 4.40 |
No.12 | 24 | 4.50 | 5.00 |
UNC 1/4 - 2 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø | TPI | ø mm | ø mm |
1/4 | 20 | 5.10 | 5.80 |
5/16 | 18 | 6.60 | 7.30 |
3/8 | 16 | 8.00 | 8.80 |
7/16 | 14 | 9.40 | 10.30 |
1/2 | 13 | 10.80 | 11.90 |
9/16 | 12 | 12.20 | |
5/8 | 11 | 13.50 | 14.80 |
3/4 | 10 | 16.50 | 17.90 |
7/8 | 9 | 19.50 | |
1 | 8 | 22.25 | 24.00 |
1.1/8 | 7 | 25.00 | |
1.1/4 | 7 | 28.00 | |
1.3/8 | 6 | 30.75 | |
1.1/2 | 6 | 34.00 | |
1.3/4 | 5 | 39.50 | |
2 | 4.1/2 | 45.00 |
Drill diameters for tapping threads | |||
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UNF No.2 - No.12 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø mm | mm | ø mm | ø mm |
No.2 | 64 | 1.90 | 2.00 |
No.3 | 56 | 2.15 | 2.30 |
No.4 | 48 | 2.40 | 2.60 |
No.5 | 44 | 2.70 | 2.90 |
No.6 | 40 | 2.95 | 3.20 |
No.8 | 36 | 3.50 | 3.90 |
No.10 | 32 | 4.10 | 4.50 |
No.12 | 28 | 4.70 | 5.10 |
UNF 1/4 - 1.1/2 | Thread pitch (P) | ![]() cutting tap |
![]() roll tap |
ø | TPI | ø mm | ø mm |
1/4 | 28 | 5.50 | 6.00 |
5/16 | 24 | 6.90 | 7.50 |
3/8 | 24 | 8.50 | 9.10 |
7/16 | 20 | 9.90 | 10.60 |
1/2 | 20 | 11.50 | 12.10 |
9/16 | 18 | 12.90 | |
5/8 | 18 | 14.50 | 15.30 |
3/4 | 16 | 17.50 | 18.30 |
7/8 | 14 | 20.40 | |
1 | 12 | 23.25 | |
1.1/8 | 12 | 26.50 | |
1.1/4 | 12 | 29.50 | |
1.3/8 | 12 | 32.75 | |
1.1/2 | 12 | 36.00 |