DRAWING OF The heating of steel to redness and then allowing it to cool slowly in the air. The reverse of hardening " and " tempering ." DROP The method of forging iron by driving or pressing it into a die placed under a drop hammer. It is employed when a number of forsings of the same pattern are required. A great deal of this class of work is now accomplished by the use of steam-hammers and forging presses. See MACHINE FORGING.
Fanorttrn.— The piling up of lengths of puddled bar iron in fagots or bundles for the purpose of reheating and rolling. When molten metal cools, the outside portions will set first, while the inside portions will remain fluid for some length of time. As the inner portion cools, it will contract and shrink upon itself and leave a depression on the top face of the casting. To avoid this condition the heavier portions of the casting are fed with metal through a small rod called the " feeding-rod," inserted through the runner or the riser, which by its motion keeps a passage open for the inflow of the fresh metal introduced to com pensate for the contraction. The metal used for this pur pose is called the " feeding-head." Fuss.— The box which holds the sand in which the pattern is rammed-up in the making of a mold. Flasks are made either of wood or of metal, and are parted horizontally into two or more sections. In a mold composed of two parts, the lowermost or the one which is molded first is called the " drag," and the uppermost, or the one which is on top when the casting is poured, is called the " cope." When a flask consists of more than two parts, the sections between the cope and the drag are called " checks " or " inter mediates." Flasks are provided with two loose covers called top and bottom boards, and they are designated as " two-part flasks," " three-part flasks," " four-part flasks," etc., according to the number of the component parts.
Ft.00g A flat-ended iron tool employed for ramming over large surfaces of sand.
Fume's.— Substances used in a smelting furnace for com bining with the earthy and other infusible matter present in ores, and which require to be separated from the metal, and which cannot otherwise be rendered fluid at the tem . perature of the furnace. The flux most widely used is a carbonate of lime in the form of limestone, clam and oyster shells, chalk, dolomite and calcite. Magnesia, fluorspar, feldspar and calcspar are also suitable for this purpose. The by-product of the furnace secured by such flux is called " slag." The structure upon which a smith's fire is main tained. Forges are constructed of brick, or brick and iron combined, or entirely of iron. A forge consists of a hearth, tuyere. chimney, bonnet and troughs for water and coal. The blast may be produced either by bellows, or by rotary blowers or a fan.
Short, conical projections cast upon the core plates and the plates of loam-molds for the purpose of assisting the adhesion of the loam. The term is also applied to the hooks of cast iron or of wrought iron which are hung from the crossbars of a molding box into the mold to prevent the sand from sliding out when the cope is lifted. They are necessary when the body of sand is more than sixteen inches square in area.
The opening in the sand of a mold, which connects the " sprue with the interior of the mold. The spree is the orifice through which the molten metal is poured into the mold. Both terms are also applied to the bodies of metal which occupy the respective passages after the cast ing has been poured.