A very unusual set of heavy-duty "turns" not intended to be driven by the usual rather inconvenient bench-mounted countershaft but by an integrated DC motor running from a 6-volt battery. To vary speeds two methods were employed, a direct-contact rubber roller (that allowed the force delivered to be varied) and a 3-step pulley for round-belt drive. However, as the motor was a DC type, it would also have been very easy to set up a simple variable-speed controller. Hence, this was a set of turns supplied in a ready-to-run state that might, in its class, be unique. It was also sold complete with a storage box and the Turns mounted on a wooden base that sat on anti-vibration rubber buffers. A plug to connect the battery was provided on one end of the base and the electrical wiring and switch were both built neatly in. As the motor was a DC type, the plug could be inserted either way to select, if needed, either forward or reverse rotation.
The maker, Rudolf Flume, claimed that the unit was a "Fine quality pair of watchmaking "turns" with a special shielded low-current motor. The ideal solution for a motorised drive on the finest of turning work."
To reassure the owner that no magnetism would be transmitted to the delicate parts upon which he was working, the makers reported that: "The motor is completely shielded against magnetism and, according to testing by the Reich Physical-Technical Institute, is free of any magnetic influence."
It was available with various battery types and accessories as follows (the translation might not be accurate):
Nr. 7990 Fine turns with a shielded low-current motor in a wooden box
Nr. 13189 6-volt battery. It is recommended to use a battery instead of the box battery, which you can have charged by any installer for a few pennies
Nr. 13240 Accumulator 4 volts, 27 amp/hours in a glass container with a support bracket
Nr. 7901 'Trunnion' protector brochure with two 'trunnion' protectors
Nr. 7903 'Counter broach' with eccentric hole and 2 different tenon protectors
Also included is one hollow-point tip with a line roller and an adjustable driver, one graver support, one special brooch with a screw disc and a disc with 10 countersunk holes, the tips being arranged eccentrically. The centre pieces of the counter brooch are drilled to the outer edge so that you can easily access the workpiece. The guide of the graver rest is provided with a spring that allows it to be gently adjusted to the desired height.
Power consumption is very low. With a box battery of 6 volts, you have a sufficient power source for a long time. The motor works almost silently and without any vibration.