Self Tapping Screws - hole sizes
Metric
Recommended hole sizes for metric self-tappers Type AB - to DIN 7975.
The following reference values are valid only for case hardened steel Self Tapping Screws applied in a simple fastening joint with clearance holes. The tightening torques are max. 50% of the minimum breaking torque.
Prior test must be carried out for the utilisation of other screws or other sheet metal materials. Punched pilot holes must be 0.1 - 0.3mm larger and the screws must be tightened in the direction the hole was punched.
| Thread diameter | Material strength Rm (N/mm2) | Sheet metal thicknesses (mm) | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0.8 | 0.9 | 1 | 1.1 | 1.2 | 1.3 | 1.4 | 1.5 | 1.6 | 1.7 | 1.8 | 1.9 | 2 | 2.2 | 2.5 | 2.8 | 3 | 3.5 | 4 | 4.5 | 5 | ||
| ST 2.2 | from 100 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.8 | ||||||||||
| approx. 300 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.7 | 1.8 | 1.8 | 1.8 | 1.9 | 1.9 | |||||||||||
| up to 500 | 1.7 | 1.7 | 1.7 | 1.8 | 1.8 | 1.8 | 1.8 | 1.7 | 1.9 | 1.9 | 1.9 | |||||||||||
| ST 2.9 | from 101 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.2 | 2.3 | ||||||||||
| approx. 301 | 2.2 | 2.2 | 2.2 | 2.2 | 2.3 | 2.3 | 2.3 | 2.4 | 2.4 | 2.4 | 2.4 | |||||||||||
| up to 501 | 2.2 | 2.2 | 2.3 | 2.3 | 2.4 | 2.4 | 2.4 | 2.4 | 2.5 | 2.5 | 2.5 | |||||||||||
| ST 3.5 | from 102 | 2.6 | 2.7 | 2.7 | 2.7 | 2.7 | 2.7 | 2.7 | 2.7 | 2.7 | 2.8 | 2.9 | ||||||||||
| approx. 302 | 2.6 | 2.7 | 2.7 | 2.7 | 2.7 | 2.8 | 2.8 | 2.9 | 2.9 | 3 | 3 | |||||||||||
| up to 502 | 2.7 | 2.8 | 2.8 | 2.9 | 2.9 | 2.9 | 2.9 | 3 | 3 | 3.1 | 3.1 | |||||||||||
| ST 3.9 | from 103 | 2.9 | 2.9 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3.1 | 3.2 | 3.3 | |||||||||
| approx. 303 | 2.9 | 2.9 | 3 | 3 | 3.1 | 3.1 | 3.2 | 3.2 | 3.2 | 3.3 | 3.3 | 3.3 | ||||||||||
| up to 503 | 3 | 3.1 | 3.1 | 3.2 | 3.2 | 3.3 | 3.3 | 3.3 | 3.3 | 3.4 | 3.4 | 3.5 | ||||||||||
| ST 4.2 | from 104 | 3.1 | 3.2 | 3.2 | 3.2 | 3.2 | 3.2 | 3.2 | 3.2 | 3.2 | 3.3 | 3.4 | 3.5 | |||||||||
| approx. 304 | 3.1 | 3.2 | 3.2 | 3.2 | 3.3 | 3.3 | 3.4 | 3.4 | 3.5 | 3.6 | 3.6 | 3.6 | ||||||||||
| up to 504 | 3.3 | 3.3 | 3.4 | 3.4 | 3.4 | 3.4 | 3.5 | 3.5 | 3.6 | 3.6 | 3.6 | 3.7 | ||||||||||
| ST 4.8 | from 105 | 3.6 | 3.6 | 3.6 | 3.6 | 3.6 | 3.6 | 3.7 | 3.8 | 3.9 | 4 | 4.1 | ||||||||||
| approx. 305 | 3.6 | 3.7 | 3.8 | 3.8 | 3.9 | 3.9 | 4 | 4.1 | 4.1 | 4.2 | 4.2 | |||||||||||
| up to 505 | 3.9 | 3.9 | 4 | 4 | 4 | 4.1 | 4.1 | 4.2 | 4.2 | 4.2 | 4.3 | |||||||||||
| ST 5.5 | from 106 | 4.2 | 4.2 | 4.2 | 4.2 | 4.2 | 4.4 | 4.5 | 4.6 | 4.7 | 4.8 | |||||||||||
| approx. 306 | 4.3 | 4.4 | 4.4 | 4.5 | 4.7 | 4.7 | 4.8 | 4.8 | 4.9 | 4.9 | ||||||||||||
| up to 506 | 4.6 | 4.6 | 4.6 | 4.7 | 4.8 | 4.8 | 4.9 | 4.9 | 5 | 5 | ||||||||||||
| ST 6.3 | from 107 | 4.9 | 4.9 | 4.9 | 4.9 | 5 | 5.2 | 5.3 | 5.4 | 5.5 | 5.6 | 5.7 | ||||||||||
| approx. 307 | 5 | 5.1 | 5.2 | 5.3 | 5.4 | 5.5 | 5.6 | 5.7 | 5.7 | 5.8 | 5.8 | |||||||||||
| up to 507 | 5.3 | 5.4 | 5.4 | 5.5 | 5.6 | 5.7 | 5.7 | 5.7 | 5.8 | 5.8 | 5.8 | |||||||||||
Inch
Recommended hole sizes for inch Self Tappers Type AB.
The following reference values are valid only for case hardened steel Self Tapping Screws applied in a simple fastening joint with clearance holes. The tightening torques are max. 50% of the minimum breaking torque.
Prior test must be carried out for the utilisation of other screws or other sheet metal materials.
| Screw size | Threads per inch | Hole size (inches) | Drill size | Drill diameter (inches) | |
|---|---|---|---|---|---|
| Max | Min | ||||
| 0 | 48 | 0.049 | 0.043 | 56 | 0.0465 |
| 1 | 42 | 0.063 | 0.055 | 53 | 0.0595 |
| 2 | 32 | 0.077 | 0.067 | 49 | 0.073 |
| 3 | 28 | 0.09 | 0.078 | 45 | 0.082 |
| 4 | 24 | 0.103 | 0.089 | 41 | 0.096 |
| 5 | 20 | 0.114 | 0.1 | 36 | 0.1065 |
| 6 | 20 | 0.124 | 0.108 | 32 | 0.116 |
| 7 | 19 | 0.138 | 0.12 | 30 | 0.1285 |
| 8 | 18 | 0.148 | 0.128 | 29 | 0.136 |
| 10 | 16 | 0.17 | 0.148 | 21 | 0.159 |
| 12 | 14 | 0.194 | 0.169 | 14 | 0.182 |
| 1/4 | 14 | 0.226 | 0.196 | 4 | 0.209 |
| 5/16 | 12 | 0.289 | 0.251 | I | 0.272 |
| 3/8 | 12 | 0.356 | 0.31 | Q | 0.332 |
| 7/16 | 10 | 0.413 | 0.359 | W | 0.386 |
| 1/2 | 10 | 0.48 | 0.418 | 29/64 | 0.4531 |