A device and associated method for fabricating a frusto-conical structure, the frusto-conical structure having a virtual peak located at a point where a taper of the frusto-conical structure would decrease to zero if the frusto-conical structure were not truncated, the device comprising: a curving device controllable to impart curvature to a planar form of a stock; a feed system including an outer drive wheel pair of rollers and an inner drive wheel pair of rollers collectively operable to rotate the planar form of the stock and to translate the planar form of the stock in a feed direction from a source to the curving device as the planar form of the stock passes through the outer drive wheel pair of rollers and the inner drive wheel pair of rollers; and a control system in communication with the curving device and the feed system to deliver control signals to the curving device and the feed system to form the planar form of the stock into the frusto-conical structure, wherein the control system is configured to differentially drive the outer drive wheel pair of rollers relative to the inner drive wheel pair of rollers of the feed system to impart, to a portion of the stock that has not yet been deformed, a substantially rotational motion in a plane of the portion of the stock about the virtual peak of the frusto-conical structure such that each location on the portion of the stock that has not yet been deformed maintains a constant distance from the virtual peak throughout feeding.