Abstract: In a multipurpose machining unit with pneumatic spindle feed, driving is performed, starting from a motor unit (12), directly or via a flexible shaft (9). An interchangeable gear set (4) makes it possible to select the number of revolutions of the tool in accordance with its purpose. In this connection, for simultaneous use, an arbitrary number of gears (5, 6) is provided. The gears (5, 6) of the gear set (4) can be plugged together in coaxial series. The driven side of the motor unit (11) can be plugged together with the machining unit directly or by way of at least one gear (5, 6) or by way of a connecting coupling (8) for a flexible shaft (9) into a rotational connection. With the use of such a machining unit, individual spindles can likewise be operated economically.