( Originally Published 1937 )
THE smith bending over his anvil in the glow of his bright forge, is always a fascinating picture. Perhaps everyone has envied his power in dominating the strongest of our materials and moulding it to his will. Perhaps it comes as a shock to learn that after all we could do such things here' and now, if we so willed. Why not? There is nothing impossible in this idea. We could make hardware and fireplace equipment, tables and candlesticks. We could make our own stone-carving tools or wood-chisels. We could attend to small adjustments and repairs we would have done before "if only we had a forge."
The craftsman wishing to work in iron has a good start if he can use the tools and forge of the local blacksmith until he knows just what he needs for himself. Where this is not possible, he must build a forge, or buy one. A solid brick forge built up from the floor, with an arch left in the middle for dumping the ashes from the blower nozzle, is ideal. It should be built against the chimney, and a hole provided in the chimney six inches to a foot higher than the fire. Where the hole is thus set down close to the fire, the smoke is carried away very well without a hood. If a hood is used, it should communicate with the chimney by the most direct route.
On two opposite sides of the forge leave a brick loose in the wall surrounding the fire space, so that if it is necessary to heat up or weld long bars these bricks can be removed to permit the bars to bed down in the centre of the fire. Make the hearth about 18" or 22" inside and about s" deep. The blower should be purchased and the air ducts set up before the masonry is complete. If so permanent an installation is not desired, get from Sears, Roebuck or Montgomery Ward a portable forge of a size and price that fits your needs. These are provided with blower, hood and legs and are all ready to use.
An anvil that works fairly well for simple, crude work is a piece of railway track mounted on a heavy stump base. Pieces of iron pipe clamped in the vise will do, to bend the curves over. Sooner or later you will want a real steel anvil, and you will wish to have a real blacksmith's vise with a leg that goes down to the floor. The mail order stores mentioned can supply these as well as bar iron of different shapes and sizes, and the tools. It is possible to do good work with few tools, and you should start with a limited selection, adding others as you find it impossible to get along without them. You can make many of the tools yourself. Making special tongs is a valuable exercise in accurate forging and fitting.
You will need a sturdy grinder, an assortment of files, a steel try-square, a steel rule, a pair of steel dividers, a hacksaw, pliers, cold chisels, etc., a drill of some kind, preferably a blacksmith's post drill and bits to fit it, and a collection of hammers. Start with a ball-pein hammer as heavy as you can comfortably swing in one hand, and work up and down in weights from that. You will also need some swages and hot and cold cutters to fit the square holes in the anvil. Use soft coal that does not contain more than / % sulphur. To start the fire, clear out the cinders down to the air duct outlet, open it from the bottom and dump any dust and cinder into a pail set below it. Then close it ready for blowing. Make out of pine boards a box, shaped like the frustrum of a square pyramid, about six or seven inches high, three inches wide at the top and five inches wide at the base. Stand this with the small end downward over the air outlet and pack your soft coal, moistened with water, around it. Tamp the damp mixture tightly and build it up to the top of the wood, then withdraw the wooden form. Drop into the hole a good handful of lighted shavings and blowing gently, pile on bits of wood, taking care not to build it up higher than the level of the coal. As the fire takes hold of the wood, gather a little fresh coal over the top of it and bank it down, in-creasing the draft at the same time. When the damp coal begins to coke, you can pile more on top and your fire will be ready.
When you are forming bars of iron for almost any purpose: fire-dogs, tongs, bar-hinges, toasting forks, or what you will, regard the bar as so much raw material. Do not be tempted -to leave the bar its full thickness all along its length with a few hammer-marks distributed over the surface to show that it is hand-forged. You are to create things out of iron not out of bars and you are to make the iron itself flow and bend before you in the fury of your driving energy. Be not afraid to reduce the bar to half or a quarter of its weight as you taper it away from the heavier parts.
Watch a blacksmith at work and notice the rhythmic manner in which he relaxes the muscles of his arm, by allowing the hammer to bounce on the anvil for two or three seconds, every few strokes. This is the first thing you should learn. Until you do learn it you will find hammering a very tiring business.
The interest in three-dimensional work of all kinds is in the alteration and play of all three dimensions. For example, the spiral volute of a snail shell interests us because the diameter of the tube, the radius of the circle and the longitudinal progression all grow larger as we follow them with the eye. But a cork screw or a shock absorber spring move only in their lengths, not in the diameter of the wire, nor in their radii. Hence these seem to us almost as one-dimensional forms, having length, but no other dimensions. We only get the sense of a dimension when we feel that it is being "exercised" by variation.
Notice that old iron workers very well understood the value of this variety in all dimensions. It was perfectly scientific too, because the further away one gets from a fulcrum the less strength is needed in a lever: old hinges, door latches and tongs, for example.
Obtain some welding compound. This is usually filings of very pure iron that flows easily, mixed with a flux (such as borax). Thicken the parts to be welded by "upsetting," or hammering back against the end. Clean the surfaces and put them in the proper relation to one another, i.e., as you want them to be welded. Sprinkle the welding compound between the pieces and around the joint. Now heat them up to a dazzling white heat, bring to the anvil and strike smartly with the hammer until they are joined. You must hit very hard.
Brazing Malleable Iron
Have the parts neatly fitted and filed clean. Tie them together with iron wire and paint a paste of borax or boric acid, brass filings, and water, into and around the joint. Heat it up until you see the brass run into the joint, then add more brass filings or wire, if necessary. Allow to cool to blackess in the forge before disturbing.
Engraving, Chasing, and Repousse Tools
Use cast steel or drill rod of a suitable size. Anneal it by heating to redness and allowing it to cool slowly. Shape the tools with the file and the grinder or grindstone. Matting and other texture tools for chasing can be made by filing and polishing the square end of a tool, then punching little pits into it with a sharp pointed tool. A contrasting texture tool can be made by hardening the tool just described, and hammering it sharply upon the polished end of another annealed blank. Still other textures are made by filing criss-cross grooves on the end of the blank with fine knife files in square or diamond patterns. Harden and temper the tools when they are finished.
Wood-Carving and Stone-Carving Chisels
For anyone who has not worked with tool steel I give this caution: Take care not to overheat your metal by making it really white hot. If it is shooting off glowing sparks, you are burning the carbon out of it and turning it into mild steel. It should be forged at a good cherry-red, and not hammered when it is too cool. When the tools are roughly forged they should be ground, and the teeth filed in the claw chisels with a knife-edge file. Then they are hardened and tempered. Where possible you should obtain and follow the maker's instructions for tempering the particular brand of steel you are using, for some steels are best treated in oil, others in water, others require special solutions. In general you will find this a practical guide.
1. Heat to a bright cherry-red for two or three inches from the tip.
2. Quench about one to one and a half inches in the oil or water.
3. Immediately rub the scale off the quenched part with a piece of abrasive stone or brick, or a bit of emery cloth.
4. Watch the shiny surface of the metal change color as the heat travels down toward the edge from the shank. First it turns a pale straw color, then a brown, then a purple and finally a blue. When the pale straw color has just reached the edge quench the end of the tool again and gently cool off the whole tool by dipping it little by little in and out of the bath.
If the edge is too hard in use and chips easily, heat up the shank of the tool and let a little stronger color creep toward the edge before quenching again, and, similarly, if the edge is too soft, repeat the whole process and quench a little sooner.
After tempering, the tools should again be ground. The Wood-working tools should be ground and polished with emery or pumice stone and finally buffed. Wood handles should be turned on the lathe and brass ferrules cut out of pieces of tubing.
GRINDING AND SHARPENING TOOLS
High-speed (3450 R. P. M.) direct-drive motor grinders are now available at low prices. These are very useful for rough grinding of tools, and trimming of forged or cast metal. They are difficult to use for fine edge tools because they cut so fast and heat up so quickly. They should be well guarded, leaving only a small segment of the wheel exposed for working. If used much, provision should be made for exhausting the dust with a fan and pipe to a chimney or window. Goggles should be worn. Have a can of water right by the wheel, and dip the tool into it every few seconds to keep it cool. Watch the drops of water on the edge, and when they bubble up you will know that the metal is too hot and needs cooling. If the edge turns black or blue, it means that the metal at that point has been over heated and the temper drawn, leaving it soft. Use the periphery of the wheel for rough grinding and the face or side of it for the finer finishing. The nearer you can get to the center of the face the slower and finer the cutting will be. If you have a variable speed grinder, notice that it cuts much slower at a low speed and there is less heating and less danger of burning the tool. Never try to grind pen knives on a high-speed wheel. The old-fashioned water-fed sandstone wheel is by far the best for fine tools. Its hand-crank or foot pedals can easily be replaced by a pulley and belt drive. See drawing for illustration of the grinding angle and whetting angle of edge tools. Note that in the grinding solid metal is taken away from the "shoulder" of the tool to make a small angle. The whetting or honing on the oil stone is done only near the edge and makes a larger angle.
The double-faced variety of carborundum stone having "coarse" texture on one side and "fine" on the other is useful where there is no grinding wheel, or where—as in schools—the pupils are not to be trusted to use it; otherwise the coarse is not so much used, since the grindstone would do as good a job more quickly. The "fine" side is the same size grit as single face ordinary carborundum stones. These are useful for preparing a new edge after the tool comes from the grindstone or has been worn back by repeated honing on the Arkansas or Washita stones,—fine translucent white stones, the Arkansas being more uniform.
Remove the "feather-edges" of plane blades and flat chisels by pushing them forward on the stone while holding the back of the blade absolutely flat on the stone. To remove the feather edge on gouges and wood-carving tools you will require Arkansas "slip stones" or stones having wedge, round or elliptical cross sections that fit inside the edges. It is useful to have shaped stones for the outside as well, but not necessary, because the tool can be rotated on a flat stone while being moved back and forth. Use pieces of smooth, firm leather for stropping the tools after they have been honed on the Arkansas.
A useful device for honing the inside of the round chisels and gouges is made this way. Turn up a piece of wood on the lathe to a long tapering cone shape, representing from one extremity to the other the range in inside diameters of your gouges. Then rub some liquid glue on to its surface and dust it with emery flour, rolling the cone back and forth through the flour, which should be spread out on a clean paper. When this is dry put it between the centers of the lathe and spin it. Your chisels will quickly respond to a little pressure on this.