Extraction or hollow drill bits, where the drilling dust is evacuated directly during drilling, become more and more common. Such drill bits offer a high potential for the reduction of dust at construction site.
From the side of Prüfgemeinschaft Mauerbohrer e. V. (PGM), there are no reservations against the use of such drill bits for reliable anchor installations. Extraction drill bits are certified by PGM in the same way as conventional drill bits, taking into account the criteria, which influence the borehole geometry like the diameters of main and minor cutting edges, there geometry and the run-out tolerance.
When extraction drill bits are used, the cleaning procedures of the borehole as defined in the ETA and in the instructions of the anchor manufacturer (e. g. brushing and blowing out) can only be skipped, if this is explicitly allowed for the respective extraction drill bit type.