Apparatus for carrying out an operation on a mechanical workpiece which operation comprises at least one stroke, or relative movement, along a predetermined path, of at least two tool members (4, 5) each being arranged on a tool carrying member (1, 2). The mechanical workpiece is positioned between the tool members (4, 5) and the tool carrying members (1, 2) are approached to each other in a first part of said at least one stroke. At least one force transferring element is arranged to be inserted by means of a low force during said first part of said stroke into a position between at least one tool carrying member and an activation element for transferring a high force during a second part of said stroke between said activation element and said at least one tool carrying member.