Abstract: The invention relates to a method for drilling, being carried out by a drilling apparatus, having a drilling device (1) that comprises a casing part (2) and a drilling unit (3), in the drilling head (I) of which there are first drilling means (4) for drilling a center hole and second drilling means (5) for reaming of the center hole for the casing part (2) as well as flushing flow arrangement (6) for flushing of waste, being generated. At least during the drilling situation, the first drilling means (4) are coupled by a power transmitting and, in order to enable removal of the same from the hole, removable arrangement, such as a bayonet coupling or like, with the second drilling means (5).

Abstract: A drilling apparatus adapted to be fed into a hole to be drilled and extendable in a longitudinal direction includes a casing and a drilling unit. A drilling head of the drilling unit includes a first drilling unit for drilling a center hole and a second drilling unit for reaming the center hole for the casing, the first drilling unit attachably connected to the second drilling unit at the drilling head. A counterpart assembly transmits rotational and impact movement from the first to the second drilling unit. A coupling assembly connects the second drilling unit with a head of the casing such that the second drilling unit freely rotates centrically around a longitudinal axis. A flushing unit for removal of drilling waste comprises at least one first passage extending through the first drilling unit to a drilling point, and communicates with at least one flow channel for transferring flushing medium to a drilling surface and the drilling point.