Self Tapping Screws - Metric Hole Sizes

Recommended Hole Sizes for Metric Self-Tappers Type AB - to DIN 7975

The following referance 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
 

Self-Tapping Screws - Inch Hole Sizes

Recommended Hole Sizes for Inch Self-Tappers Type AB

The following referance 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

Note: Due to the fact that fastening applications differ greatly, the above information is for guidance only and is correct to the best of our knowledge. The customer must satisfy themselves with the performance of the fastener and validity of the data. TR Fastenings will not be held responsible for any failure that may occur from the use of this information.