Abstract: A hand-held power tool includes a tool receptacle with which a tubular tool holder configured to receive an application tool is associated, and a locking device configured to lock the application tool in the tubular tool holder. The locking device locks the application tool in a locking position via at least one locking element in the tubular tool holder. The locking device has a locking sleeve and a pressure ring spring loaded via an associated spring element. The spring-loaded pressure ring is configured to force the locking sleeve into the locking position and, in the locking position, forces the at least one locking element against the tool holder.

Abstract: The invention herein relates to an undercutting device which is provided with a substantially tubular body adapted to be placed within a parallel-sided hole. A rotary percussion head is provided at one end of the body and has one or more cutting tools which extend radially therefrom at an obtuse angle and which cutting tools are adapted to cut outwardly from the radius of the body, means are provided for rotating the head about the axis of the body and for operating the percussion head at one predetermined depth in the hole so that the cutting tools may act on the wall of the parallel-sided hole.