Fullers whose shaping parts are arched or concave, resembling Fig. 224, may be used in pairs or singly ; when used in pairs, they become both fullers and gauges, because the work which is being reduced between the two fullers cannot be reduced after the two tools are brought together by hammering, without applying other tools having smaller gaps.

Such fullers are made by first preparing the shaping parts with thin ends that are about the same thickness as when finished, but having straight bottoms instead of curved ones. The forming of the arches is commenced by cutting out the superfluous pieces with a punch, or with a gouge-chisel, indicated by Fig. 226; after being thus hollowed, the shaping is completed by driving each fuller while heated into a grooved shaper, the groove being the shape of the required fuller-end. For this purpose a groove is made around a piece of round steel by means of a lathe, until the groove is of proper depth and width. If necessary, several grooves may be made into one shaper, and each groove formed for one particular work. A grooved shaper of this class is shown by Fig. 225.

After the intended fullers are cut with punching or gouging, the grooved shaper may be held with tongs between a pair of the fullers at a suitable heat, and the two tools shaped by sledge-hammering the top tool; or, the fullers may be shaped separately, by putting them into the groove, and hammering the square stems which are upwards. During such hammering, the grooved shaper is held in some convenient gap or gaps to keep it in position. The finishing of the arches consists in filing off the burrs that were produced by the shaping processes, and after-wards filing the extremities to the required dimensions.