Technical information

Drill size

Forming taps

ISO Metric corse thread
ISO Metric coarse thread DIN 13
ISO Metric coarse thread DIN 13
M Pitch[mm] Drill size[mm]
2 0,4 1,85 ± 0,03
2,5 0,45 2,30 ± 0,03
3 0,5 2,80 ± 0,03
3,5 0,6 3,25 ± 0,03
4 0,7 3,70 ± 0,03
5 0,8 4,65 ± 0,03
6 1 5,55 ± 0,05
8 1,25 7,40 ± 0,05
10 1,5 9,30 ± 0,05
12 1,75 11,20 ± 0,05
14 2 13,10 ± 0,05
16 2 15,10 ± 0,05
18 2,5 16,90 ± 0,05
20 2,5 18,90 ± 0,05
24 3 22,70 ± 0,05
27 3 25,70 ± 0,05
30 3,5 28,45 ± 0,05
Other drill sizes
Theorical flank diameter + pitch/5.
Note
In order to obtain the requested tolerance, the formation of a complete internal thread and guarantee the tap tool life, it is important to respect the drill hole diameters and their tight tolerances. The core diameter of the internal thread obtained by forming is not only a function of the drill hole diameter but also depends on the workpiece material properties. For this reason the tolerance on the core diameter is 7H compared to 6H for cutting taps. For more detailed information see the DIN 13-50 standard.
ISO Metric fine thread
ISO Metric fine thread DIN 13
ISO Metric fine thread DIN 13
MF Pitch[mm] Drill size[mm]
3 0,35 2,85 ± 0,03
4 0,5 3,80 ± 0,03
5 0,5 4,80 ± 0,03
6 0,75 5,65 ± 0,03
8 1 7,55 ± 0,05
10 1 9,55 ± 0,05
10 1,25 9,40 ± 0,05
12 1 11,55 ± 0,05
12 1,25 11,40 ± 0,05
12 1,5 11,30 ± 0,05
14 1,25 13,40 ± 0,05
14 1,5 13,30 ± 0,05
16 1,5 15,30 ± 0,05
18 1,5 17,30 ± 0,05
20 1,5 19,30 ± 0,05
Other drill sizes
Theorical flank diameter + pitch/5.
Note
In order to obtain the requested tolerance, the formation of a complete internal thread and guarantee the tap tool life, it is important to respect the drill hole diameters and their tight tolerances. The core diameter of the internal thread obtained by forming is not only a function of the drill hole diameter but also depends on the workpiece material properties. For this reason the tolerance on the core diameter is 7H compared to 6H for cutting taps. For more detailed information see the DIN 13-50 standard.
Whitworth pipe thread - EN ISO 228
Whitworth pipe thread EN – ISO 228
Whitworth pipe thread EN - ISO 228
G Pitch[TPI] Drill size[mm]
1/8″ 28 9,25 ± 0,05
1/4″ 19 12,50 ± 0,05
3/8″ 19 16,00 ± 0,05
1/2″ 14 20,00 ± 0,05
3/4″ 14 25,50 ± 0,05
1″ 11 32,00 ± 0,05
Other drill sizes
Theorical flank diameter + pitch/5.
Note
In order to obtain the requested tolerance, the formation of a complete internal thread and guarantee the tap tool life, it is important to respect the drill hole diameters and their tight tolerances. The core diameter of the internal thread obtained by forming is not only a function of the drill hole diameter but also depends on the workpiece material properties. For this reason the tolerance on the core diameter is 7H compared to 6H for cutting taps. For more detailed information see the DIN 13-50 standard.
Unified coarse thread UNC ASME - B1.1
Unified coarse thread UNC ASME – B1.1
Unified coarse thread UNC ASME - B1.1
D Pitch[TPI] Drill size*[mm]
Nr. 8 32 3,80 ± 0,03
Nr. 10 24 4,35 ± 0,03
Nr. 12 24 5,00 ± 0,03
1/4″ 20 5,80 ± 0,03
5/16″ 18 7,30 ± 0,05
3/8″ 16 8,80 ± 0,05
7/16″ 14 10,30 ± 0,05
1/2″ 13 11,80 ± 0,05
5/8″ 11 14,85 ± 0,05
3/4″ 10 17,90 ± 0,05
Other drill sizes
Theorical flank diameter + pitch/5.
Note
In order to obtain the requested tolerance, the formation of a complete internal thread and guarantee the tap tool life, it is important to respect the drill hole diameters and their tight tolerances. The core diameter of the internal thread obtained by forming is not only a function of the drill hole diameter but also depends on the workpiece material properties. For this reason the tolerance on the core diameter is 7H compared to 6H for cutting taps. For more detailed information see the DIN 13-50 standard.
Unified fine thread - UNF ASME B1.1
Unified fine thread UNF ASME – B1.1
Unified fine thread UNF ASME - B1.1
D Pitch[TPI] Drill size*[mm]
Nr. 8 36 3,85 ± 0,03
Nr. 10 32 4,45 ± 0,03
Nr. 12 28 5,10 ± 0,03
1/4″ 28 5,95 ± 0,03
5/16″ 24 7,45 ± 0,05
3/8″ 24 9,05 ± 0,05
7/16″ 20 10,55 ± 0,05
1/2″ 20 12,15 ± 0,05
5/8″ 18 15,25 ± 0,05
3/4″ 16 18,35 ± 0,05
Other drill sizes
Theorical flank diameter + pitch/5.
Note
In order to obtain the requested tolerance, the formation of a complete internal thread and guarantee the tap tool life, it is important to respect the drill hole diameters and their tight tolerances. The core diameter of the internal thread obtained by forming is not only a function of the drill hole diameter but also depends on the workpiece material properties. For this reason the tolerance on the core diameter is 7H compared to 6H for cutting taps. For more detailed information see the DIN 13-50 standard.

More info

If you have not found the information you are looking for, contact us, our technical department will reply as soon as possible.

Contact us

Search in the site

Search the entire site, products or technical information.