Practical forging and art smithing

by Thomas F. Googerty

CHAPTER I.

The Forge—Forge Tools—The Anvil—Anvil Tools—Making the Fire—Cleaning the Fire—Welding—Flux and Its Uses.

One of the most essential things in the school forge shop is a good forge and fire; half the work is then mastered. A few years ago nearly all of the small commercial shops running from one to six or more fires were equipped with brick or iron forges. The blast was furnished either with a bellows or fan which had to be turned by hand. This method was a great drawback, which resulted in much loss of time. It was impossible to do much work without the aid of a helper. Work that required two men in those days is being done now by one. Modern invention has played an important part in simplifying the labors of the workers in iron and steel. At the present time there are various kinds of forges in use that lessen the work of the smith. The most successful factories are now equipped with modern forges and appliances in order that they may be able to do work quickly.

In our manual training schools, where the pupils have such short periods in which to do work, it is necessary that the shops be equipped with modern tools so that they can produce work quickly. This will give the individual pupil more practice in a shorter length of time, which simply means more knowledge. Our schools should not be hampered by using forges that have been out-of-date for years.

The best forge for manual training and trade schools is the down draft with power driven fans, thus eliminating all pipes overhead and doing away with the dust and dirt. A boy, working at this kind of a forge, can use both hands in the handling of the work being heated in the fire; this is a great advantage over the old way of turning a crank. Another good feature of the mechanical draft forge is that it teaches a boy early how to avoid over-heating or burning his iron. This is the first thing one must learn in working at forging, as one who cannot heat the metal properly cannot work it. One must become acquainted with the material, and the burning heat must be understood.

Fig. 1. A Typical School Forge.

Fig. 2. Fire Tools.

[Figure 1] shows an illustration of a down draft forge suitable for schools; it is made of cast iron. A pressure fan furnishes the blast for the fire and an exhaust fan takes away the gas and smoke thru an opening at the bottom of the hood, and thru a large pipe which continues under the floor and out thru a flue. The hood represented at A, can be moved backward and forward to catch the smoke. The hood is moved with a crank and worm gear as shown at B. The hearth is shown at C; a hole in the center is called the tuyere. This is where the fire is built and is the outlet for the wind. The amount of air needed for the fire is regulated by a valve that is moved with a rod shown at D. The coal box is always at the right hand of any forge and is shown at E. The water box is represented at F. At G is shown the pressure pipe and at H the exhaust pipe. Notice the large opening under the forge at I. Thru this opening any nut or screw under the tuyere can be tightened with ease. Notice the slide-rod at J. This rod, when pulled, dumps the cinders out of the tuyere, and a bucket may be set under the hearth to catch them. In school shops these forges are generally set in pairs in order to save room. [Figure 2] shows three fire-tools needed for the forge fire. These tools consist of a poker made from ⅜-inch round stock, 26 inches long with a loose eye turned on one end for a handle; a shovel with a flat blade 4 by 6 by ¹⁄₁₆ inches with a handle riveted to the blade, and a tool called a scraper. This scraper is made from the same stock as the poker and is made with an eye at one end and a flat hook at the other. It is used to scrape the coal and coke onto the fire, and to move pieces of coke or coal, so that the iron may be seen while heating.

Fig. 3. Anvil.

The anvil should be of wrought iron with a steel face, weighing about 125 pounds. This is large enough for any work being done in manual training schools. In the school shop the anvils should all be of the same size and weight so that any tool used with them will fit into any square hole. In factories where anvils are made, they are forged from wrought iron or soft steel, with a carbon steel face welded on; some are cast steel thruout and others are cast iron with a steel face. The face is generally three-quarters inch thick, and is hardened to resist heavy blows from the hammer and sledge. (See drawing [Figure 3] of anvil.) The anvil should be fastened with iron straps, on a 10 by 10-inch block, set into the ground about 3½ feet. From the top of the anvil to the floor should measure 26 inches. The proper place to set the anvil in relation to the forge is shown in the drawing, [Figure 4]. The smith should stand between the forge and the anvil, with the horn of the anvil at his left when facing it. The anvil edge farthest from the smith is called the outer edge and the one nearest the smith is called the inner edge.

Fig. 4.

Fig. 5. Hammer. Fig. 6. Sledge.

Fig. 9. Punch. Fig. 7. Hardie.

Fig. 8. Hand Punch.

Fig. 10. Center Punch.

Every anvil should have two ball hammers weighing about 1½ and 2 lbs. each. (See drawing of hammer, [Figure 5].) The hammers should be numbered corresponding with a number on the anvil. All the hammers should be kept in a rack when not in use. When the pupils come into the shop to work, they should be assigned to a certain forge and held responsible for the care of tools. A ten-pound sledge hammer should also be included, perhaps one for every two forges; the handle should be 26 inches long. (See [Figure 6].)

A piece of tool steel fitted into the square hole of the anvil and sharpened at the top, is called a hardie. It is used in cutting iron. A piece of iron is set on the sharpened edge of the hardie and struck with the hammer. The sharpened edge of the hardie cuts into the iron, and in this manner it is cut deep enough so that it may be broken. (See drawing of hardie, [Figure 7].)

If a piece of steel is pointed on one end, it can be hammered thru a flat piece of iron. This is one method of punching holes in iron; a steel punch so made is called a hand punch. Ordinarily hand punches are made out of ½-inch to ¾-inch hexagonal tool-steel bars about eleven inches long. (See drawing [Figure 8].) For heavy punching, a short, thick punch with a hole thru it, (called the eye) to receive a wooden handle, is used. This kind of punch is struck on with a sledge hammer. (See drawing [Figure 9].)

A center punch is used to make depressions in metal so that a drill may be started in a given place. It is used also to mark places or distances on the surface of metal when the metal is to be bent at a certain place. Center punches are made from hexagonal tool steel about 4 by ½-inch, drawn to a point and ground to a short angle. (See [Figure 10].)

Fig. 11. Flat Tongs.

Fig. 12. Hot Chisel. Cold Chisel.

Fig. 13. Flatter. Fig. 14. Set Hammer.

In heating and handling short pieces of stock, tongs are used (see [Figure 11]) which are made from Swedish iron or mild steel; they are made in various sizes and shapes according to use. They are called pick-ups, flat, round-nose, and bolt tongs according to the shape of the lips. Tongs should always be made to fit the piece being forged. One cannot hold a piece of iron properly with tongs that do not fit the piece. They may be heated and fitted to the stock when occasion demands. One important reason why tongs should fit the piece being hammered, is that when turning and striking the piece there is danger of the piece being knocked out of the tongs in a whirling motion and the flying piece of hot iron is liable to strike someone; this danger must be closely watched. Tongs should not be heated red hot and cooled in water; this destroys them.

Hot and cold chisels are used in cutting stock. The blade of the hot chisel is made very thin, while the cold chisel is made blunt to stand the heavy strain in cutting. They are generally made with a hole thru them, called the eye, to receive a wooden handle. These chisels are struck on with a sledge hammer. (See [Figure 12].)

Iron and steel are sometimes smoothed with a tool called a flatter. This tool is struck on with a sledge, and should not be used to stretch iron. Its purpose is only to give the work a smooth finish. [Figure 13] shows a flatter, and [Figure 14] a set-hammer. The set-hammer is always used to smooth and draw stock. All of these tools are made from tool-steel.

A heading tool is made from a flat piece of soft steel with a hole in one end. Sometimes a carbon steel face is welded on. The heading tool is used mostly in heading bolts. Heading tools are made with different sized holes. (See [Figure 15].)

Fig. 15. Heading Tool.

Fig. 16. Top and Bottom Swages.

Swages and fullers are used to smooth and form iron into various shapes. The swages generally have half round depressions in them. They are made in pairs called top and bottom swage. The bottom one fits the square hole of the anvil; the top one has a hole for a wooden handle. (See drawing [Figure 16].) The fullers are also made in pairs called top and bottom fullers. They are used to make depressions in metal. (See drawing [Figure 17].) When referring to swages, fullers, and other tools of this character, blacksmiths speak of anvil tools. Special anvil tools are used in doing various kinds of forging, and are made when needed. The anvil tools should be kept in a tool rack next to the anvil. These tools should be made from tool-steel of about 75-point carbon, or they may be purchased from a dealer. Some tools, such as swages, that do not require continuous service, are made of soft steel.

The anvil tool should have a buggy-spoke for a handle. The handle should stick thru the eye of the hole about one inch and should never be wedged. If the handle is wedged it is more liable to be broken when the tool is struck a glancing blow with the sledge hammer. This is very often the case. The reason the spoke should stick thru the tool is that if it should begin to work off the handle when struck with the sledge hammer, the movement can be seen.

Fig. 17. Top and Bottom Fullers.

[Figure 18] shows a wrought vise suitable for school work. A cast iron machinists’ vise should not be used excepting, perhaps, for bench work. [Figure 19] shows a cast-iron swage block with various sized holes, and depressions around the edge for forming iron.

The stock used in a forge shop should be kept in a rack built for the purpose. The different kinds of stock, such as soft and tool-steel, common and Swedish iron, should be partly painted with a distinguishing color, so that there will be no trouble finding what is wanted. For instance, all soft steel should be painted white, tool-steel another color, and so on. There should also be in the shop a shears to cut iron. One of the ordinary hand-power shears in use today would be suitable and may be purchased from a dealer.

Fig. 18. Vise.

Fig. 19. Cast Iron Swage Block.

In lighting the fire in the forge all of the cinders are cleaned out down to the tuyere. This is done by scraping them to the sides of the fire-place with the shovel. All clinkers should be picked out with the hands and put under the forge. It is a good plan to pick out some of the best pieces of coke and set them to one side on the forge, to be used later on. The slide rod that controls the ash dump at the bottom of the tuyere, is now pulled to allow the cinders and ashes to drop thru. Do not allow a boy to pull the valve after the fire is started, as this wastes the coke and is a bad habit to get into.

When the tuyere is clean, some shavings are lighted in the bottom and when well burned, the coke is raked back on the fire. A little wind is then turned on. Wet coal is banked around the sides and back of the fire. When the fire is well started and loosened up in front with the poker and most of the smoke burned, it is ready for heating. The coal in the box should be thoroly mixed with water before putting it on the fire, for the reason that it cokes better, and packs in around the sides of the fire, keeping it from breaking thru. The coal box is always at the right of the worker when he is facing the fire. The box on his left, and between the down draft forges, is to hold water—not coal. There should be a water cup of some sort hanging on a hook so that when water is needed for fire or coal it may be handled with the cup.

A fire, when not properly handled becomes hollow, due to the center burning out. If iron is heated in this kind of a fire, it will become oxidized, that is to say, a dirty scale will form over the metal. Iron cannot be properly heated, and it is impossible to get the welding heat with a fire in this condition. The reason a fire becomes hollow is that it may be filled with clinkers, or too much blast may have been used, and when it comes in contact with the pieces being heated causes them to cool and oxidize. Sometimes the fire will not be directly over the hole in the tuyere; which is one cause of poor heating. This is a common fault with boys working at the forge. Always have the fire over the hole in the tuyere, and not to one side.

When the fire becomes hollow and dirty, clean it by picking out the clinkers with the poker or scraper, then move the sides of the fire towards the center of the tuyere with the shovel, keeping the well-coked inner sides near the center of the tuyere, and having the center of fire over the hole in the tuyere. Wet coal is now banked around the outer sides. Always have a thick bed of coke under the piece being heated and regulate the blast so as not to burn out the center of the fire at once. See drawing of fire with piece about on the same plane with bottom of hearth; notice dotted lines representing the wrong way to put stock in the fire. ([Fig. 20.])

Fig. 20. Section of Forge Fire.

If two pieces of iron are placed in the fire and heated, they will become gradually softer until they reach a state where the metal has become sticky. If touched together the two pieces will stick. This is what is known as welding heat. If they were taken to the anvil and hammered while in this condition they would unite and become one piece. This would be called welding. All metals cannot be welded. Iron, soft steel, low-carbon tool steel and spring steel can be welded.

A flux is used in welding steel—this excludes the air and forms a pasty surface on the metal which is squeezed out from between the surfaces of the metal when hammered. Borax and the many welding compounds are used. Very seldom is it necessary to use a flux on iron. Clean sand, which is good, is used by many. Borax or welding compound is sometimes used on very thin stock. For ordinary welding, such as is being done in school shops, borax should never be used. It is poor practice, unnecessary, and a useless waste.

In heating iron, if it is brought beyond the welding heat, it will become softer and softer until it will finally burn. This may be known by the great number of little explosive sparks coming from the fire. These little sparks are particles of iron separating from the bar and burning. As the heat gradually rises, the metal separates. If the bar were now placed on the anvil and struck a hard blow with a hammer, it would fly to pieces. Therefore, judgment must be used in striking the first blow on any welding heat—it should be light. The succeeding blows should be made gradually harder. A hard blow at the start might make the metal fly to pieces, or make the upper piece slip away from the under piece. If lighter blows were struck, the weld might be made in good shape.

The principal thing in welding is to have a clean fire. All of the clinkers must be kept out. The fire should be a well burned one, without much smoke or gas, and never any green coal near the pieces being heated. Well burned pieces of coke around the metal should always be used in raising the welding heat. In raising the welding heat very little blast should be used at first. Heat the pieces slowly so as to get them hot thruout.