To know the ideal power to use during an installation of a concrete screw, is important to first know the correct installation procedure that is shown in the ETA 20/0046 approval:
- Drill: Make a hole in the base material with the correct diameter and depth, using a drill bit in rotation and hammer mode.
- Blow and clean: Clean the hole of dust and drill fragments using a hand pump, compressed air or a vacuum cleaner.
- Install: Choose an impact gun or a torque wrench that does not exceed the maximum torques Timpact,max or Tins,max respectively. Connect the installation socket or tip to the gun or torque wrench. Assemble the anchor head on the socket/tip.
- Apply Torque: Guide the anchor into the hole with an impact wrench through the anchor plate until the head of the anchor is in contact with the anchor plate. The anchor must be tight after installation. Do not twist the head of the anchor to loosen it.
Note: This process can also be done manually with a torque spanner.
Power required for installation
Once this procedure has been carried out, we focus on point number 4.
To apply the appropriate torque to our anchor we must consult the approval again (ETA 20/0046) which indicates different gun power/torque values depending on the metric, to Below, the specific case of THE is explained (the values for TXE, TFE, may vary, consult ETA).
| Metric | Equipment | Power |
| THE M6 | Bosch GDS 18E, 500 W. | Timpact,max 250 Nm. |
| THE M8 | Makita TW0350, 400 W. | Timpact,max 350 Nm. |
| THE M10-M12-M14-M16-M18 | Bosch GDS 24, 800 W. | Timpact,max 600 Nm. |
Any other gun other than those previously named, but that are equivalent in power, are validated for correct installation by this document: ETA 20/0046.
What are the problems of a wrong choice of impact gun?
Using an impact gun improperly can lead to the following disadvantages:
- Over-torque: The power/torque applied to the anchor is greater than that described in the approval, so when the anchor touches the plate to be fixed, it receives an excess of torque that causes it to break in the area of the wire rod, where the threaded part ends.
- Reduced torque: The power/torque applied to the anchor is less than that described in the approval, so the installation is excessively expensive in terms of time, even if the anchor cannot be installed completely.
Choosing the right tool and power is key to a safe and durable installation of concrete screws. Always consult the ETA 20/0046 certification to ensure the best result.
If you have any questions or need more information, please do not hesitate to contact our technical team.
