The square for threading
There is a square at the shank end of each tap manufactured to DIN. There is a standard to ensure that tool holders and taps fit together. This standard (DIN 10: Square of cylindrical shanks for rotating tools) defines the dimensions for inner square and outer square per nominal size.
An example of an external square with the nominal dimension 4.9 mm:
its side length must not exceed 4.9 mm and must be at least 4.780 mm. The length of the square is fixed at 8 mm. In addition, the shaft diameter range is also specified: It should be between 5.79 mm and 6.53 mm, preferably 6 mm.
Comparison table: square shank for taps DIN 352, 371 and DIN 376
If we take a look at the nominal dimensions of the common taps DIN 352, 371 and DIN 376, the overall picture is as follows:
| Shaft-∅ x square | DIN 2184-2 | DIN 2184-1 | DIN 2184-1 |
| mm | (DIN 352) | (DIN 371) | (DIN 376) |
| 2,5×2,1 | M1-M1,8 | M1-M1,8 | — |
| 2,8×2,1 | M2-M2,5 | M2-M2,5 | M4 |
| 3,5×2,7 | M3 | M3 | M5 |
| 4×3 | M3,5 | M3,5 | — |
| 4,5×3,4 | M4 | M4 | M6 |
| 6×4,9 | M5-M8 | M5-M6 | M8 |
| 7×5,5 | M10 | — | M10 |
| 8×6,2 | — | M8 | — |
| 9×7 | M12 | — | M12 |
| 10×8 | — | M10 | — |
| 11×9 | M14 | — | M14 |
| 12×9 | M16 | — | M16 |
| 14×11 | M18 | — | M18 |
| 16×12 | M20 | — | M20 |
| 18×14,5 | M22-M24 | — | M22-M24 |
Important!
At this point, it is permissible to refer to ISO standard 237 and ASME B94.9 (US standard), in which squares deviating from the DIN standard are standardized.
What function does the square have?
The square is used to absorb the torque required for thread cutting. Both directions of rotation must be operated. The special feature of thread cutting is the reversal of the direction of rotation in the thread cutting process.
Which different tool holders are available?
First you have to distinguish whether you want to cut a thread by hand, with a hand-held machine (cordless screwdriver, drill) or with a machine tool.
1. by hand
The classic operating tool or holding tool for taps is the adjustable tap wrench (here you can find more information about the adjustable tap wrench). It holds the tap in the square and the force is transferred via the square by the leverage of the handles. The adjustability of the hardened jaws makes it possible to accommodate taps with different square sizes.
Overview table: Which tap fits which tap
Hier eine Tabelle der Haltewerkzeuge mit den unterschiedlichen Vierkanten.
| NORM | DIN 1814 | ||||
| Adjustable tap wrench | |||||
| Size | suitable for | length | steel | ||
| mm | Art. No. | ||||
| Nr. 0 | W 1/16-5/16 | — | M 1-8 | 120 | 00602020 |
| Nr. 1 | W 1/16-3/8 | — | M 1-10 | 175 | 00602030 |
| Nr. 1.1/2 | W 1/16-1/2 | G 1/8 | M 1-12 | 175 | 00602040 |
| Nr. 2 | W 5/32-1/2 | G 1/8 | M 4-12 | 265 | 00602050 |
| Nr. 3 | W 7/32-3/4 | G 1/8-1/2 | M 5-20 | 370 | 00602060 |
| Nr. 4 | W 7/16-1 | G 1/4-3/4 | M 9-27 | 480 | 00602070 |
| Nr. 5 | W 1/2-1.1/4 | G 1/4-1 | M 12-33 | 730 | 00602080 |
| Nr. 6 | W 3/4-1.5/8 | G 1/2-1 1/4 | M 18-42 | 1000 | 00602090 |
| Nr. 7 | W 1 – 2.1/8 | G 3/4-1 3/4 | M 25-52 | 1250 | 00602100 |
| Nr. 8 | W 1-2.1/2 | G 3/4-3 | M 25-68 | 1250 | 00602110 |
2 . Hand-held machine (cordless drill)
The situation is different when tapping with a cordless screwdriver or cordless drill. Here the use of so-called quick-change inserts is useful. Here you need a special quick-change insert for each square size.
Overview of quick-change threading inserts
| Shaft-∅ x square | DIN 2184-2 | DIN 2184-1 | DIN 2184-1 | |
| mm | (DIN 352) | (DIN 371) | (DIN 376) | Art. No. |
| 2,5×2,1 | M1-M1,8 | M1-M1,8 | — | 04839010 |
| 2,8×2,1 | M2-M2,5 | M2-M2,5 | M4 | 04839020 |
| 3,5×2,7 | M3 | M3 | M5 | 04839030 |
| 4×3 | M3,5 | M3,5 | — | 04839040 |
| 4,5×3,4 | M4 | M4 | M6 | 04839050 |
| 6×4,9 | M5-M8 | M5-M6 | M8 | 04839060 |
| 7×5,5 | M10 | — | M10 | 04839070 |
| 8×6,2 | — | M8 | — | 04839080 |
| 9×7 | M12 | — | M12 | 04839090 |
| 10×8 | — | M10 | — | 04839100 |
| 11×9 | M14 | — | M14 | 04839110 |
| 12×9 | M16 | — | M16 | 04839120 |
| 14×11 | M18 | — | M18 | 04839130 |
| 16×12 | M20 | — | M20 | 04839140 |
| 18×14,5 | M22-M24 | — | M22-M24 | 04839150 |
3. machine tool (tapping chuck)
Special tapping chucks are used for machine tools. The selection of these chucks is decisively determined by the type of machine and the type of process generated by it. For this reason, there are a large number of holders and chucks with different performance characteristics that require special consideration.
If you have any questions about thread cutting, we look forward to hearing from you. Please write to us under info [@] gsr-germany.de. We will be happy to advise you!
