Abstract: An adapter for operating a keyhole saw (10) on a driving machine includes a driving section (17; 117) for absorbing torque and a threaded section (18; 118) screwed into a threaded hole (20) in the keyhole saw (10). A driving segment (16; 116) is offset radially relative to the adapter axis and is inserted in a form-fit manner into a receiving hole (21) present in the keyhole saw (10). The driving segment (16; 116) is located in an axially extending manner on the end of a driving element (12; 112) which includes the driving element section (17; 117). The threaded section (17; 117) is formed on a threaded mandrel (13; 113) which is situated in the driving element (12; 112) and is non-detachably connected thereto. The threaded mandrel (13; 113) is held in the driving element (12; 112) in a rotatable manner to be axially displaceable to a limited extent.

Abstract: The invention relates to an adapter (11) for operating a hole saw on a prime mover, particularly an electric hand drill, comprising a driving segment (17) for taking up torque and a threaded segment (18) for screwing into a threaded hole present in the hole saw, and at least one driving dog (16) for entering a receiving hole present in the hole saw. In order to obtain a zero-clearance connection between the adapter (11) and hole saw and simple usability when joining the adapter (11) and the hole saw, the at least one driving dog (16) on the end of a driver (12) having the driving segment (17) facing the hole saw is disposed axially protruding, and the threaded segment (18) is formed on a threaded mandrel (13), and the threaded mandrel (13) is permanently rotatably and axially displaceably held in the interior of the driver (12).