Read Ebook: Os meus amores: contos e balladas by Coelho Trindade

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The welding of two pieces of stock by scarfing and lapping is known as a separate-heat-weld, so called because the pieces are detached while the heat is taken. In making any kind of a weld there is more or less stock wasted in the raising of the welding heat, therefore the parts to be lapped and welded are always upset or thickened and then scarfed. The word "scarfed" means the shaping of the ends of the bars so that when heated and lapped one on top of the other, they will fit and make a splice, leaving the stock when hammered about its original size.

The method of upsetting is to heat the ends of the bar, then set the hot end on the anvil with the bar vertical and hammer on the other end. This thickens the heated end. If it is a long heavy bar, the worker churns the bar up and down striking the hot end on the anvil. A bar may also be heated on the end, then fastened in a vise and the hot part hammered to thicken it. In upsetting, the bar must be kept straight as hammering will bend it where heated; if not kept straight, it will not thicken.

When a piece is upset about one inch in diameter for a three-quarter inch, round bar, it is scarfed by setting the hot end on and near the outer edge of the anvil. It is then driven back on a bevel by hammering. See Figure 22. It is also turned on the side and beveled on both sides to nearly a point. See Figure 23. The scarf must not be hammered when the piece is held in the center of the anvil, , for the reason that the edge of the hammer comes in contact with the anvil, pecking dents in it or breaking out pieces from the hammer.

Another method of scarfing is to hammer the end partly back as previously explained, then set the piece on the inner edge of the anvil and hammer it as shown in Figure 25. After each blow, it is drawn away from the edge of the anvil just a little; this tapers it with a series of little steps, not for the purpose of making notches in the scarfs to fit together and hold while hammering, but simply because the edge of the anvil leaves it in this condition when tapered. It is also drawn pointed by hammering on the outer edge of the anvil.

Theory teaches that the scarf should be made with the beveled part convexed. However, in practice, it is made to look like the drawing in Figure 26. Note the raised parts at "D". This is forced up when the scarf is first driven back with the hammer as shown at "B".

The reason that the high part should be on the scarf, is, that when lapped it gives an additional amount of stock at this part of the laps to be hammered. If the scarfs are made flat, when hammered, they are not liable to finish up without having the pieces thin, or the point of the lap exposed. If the scarfs are made concave, it is claimed by some workers of iron that dirt will deposit there and result in a poor weld. This is true to some extent. However, dirt will deposit on any scarf unless the fire is clear. With a concaved scarf when lapped, there is not stock enough to be hammered without leaving the pieces thin, or the lapping too long when welded. Scarfs should not be made concave.

Notice in Figure 27, the incorrect way of scarfing and in Figure 28, the correct way.

The scarfs must not be made too long; this is a common fault with all beginners and one to avoid. The scarfs should be made a little longer than the thickness of the iron, perhaps 1 1/2 times the thickness.

In raising the welding heat, the pieces must be placed in the fire with the scarfs, or beveled part, down. The fire must be a clean one. A well burned fire is best. A new fire is not a good one to raise the welding heat in, as there is too much smoke and green coal that comes in contact with the metal. The hammer should be placed on the anvil about over the square hole, so it will be handy to reach when making the weld. The anvil should also be clean. A heavy hammer should be used in welding. The proper way to hold the hand hammer is with the fingers around the handle and the thumb protruding along the side and near the top. The thumb should never grip around the handle, but lie along the side to guide and direct the blows. When using the sledge hammer, stand in front of the anvil and not at its side, and let the first blow be a light one.

In heating a slow blast is maintained. When the pieces begin to get about yellow, more blast is used. The pieces can be watched without removing them from the fire. They should be turned over occasionally, moving them nearer to the surface of fire to see how the heat is progressing, and then under the coke again. Care must be taken to get both pieces heated alike. If one piece should get hotter than the other, it can be moved over in the fire a little, and the cool one put in its place. Perhaps the fire is hotter in one spot than another. If one piece is heating much faster than the other, lift it clear up and out of the fire for a few seconds to cool and give the other piece a chance to become hotter. If the points of the scarf are heating too fast for the body, the pieces must be pushed thru the fire a little farther.

It is a good plan sometimes, when the pieces are about a yellow heat to shut off the wind for a moment, to let the pieces and fire even up and give the heat a chance to soak thru them. As the pieces become nearly white, the blast is increased. Welding heat is about 1900?-2000? Fahrenheit, and can only be determined by experience. When the temperature of the pieces reaches the welding heat, they are lifted up and out of the fire and taken by the smith to the anvil, without the aid of a helper. The smith raps them against one another or against the anvil to dislodge any dirt that may be on the scarfs. The piece in the left hand is set against the inner edge of the anvil. The piece in the right hand is now moved across the anvil until it comes under the top one. See Figure 29. The piece in the left hand is then placed on the under one, by simply raising the hand, teetering the piece on the edge of the anvil, and holding it firmly by pressing down. This is important. The smith lets go of the piece in his right hand, and taking the hammer strikes lightly until the two are stuck, after which he welds them together with solid blows, first on one side, then on the other and finally on the corners.

It requires some practice to be able to take two pieces from the fire and place them in position on the anvil to be welded. This should be practiced by the pupil under the eye of the teacher, perhaps a dozen or more times, with the cold pieces before he undertakes to get the welding heat. If one cannot take the pieces out and place them in position, he cannot make a weld of this kind.

Two boys should not be allowed to work together on this weld. One can do it much better than two. It is a one-man job. There is nothing difficult about it, after the method is learned by deliberate and persistent practice with the cold iron. There is no need of hurrying when taking the pieces out of the fire to the anvil.

If the scarfs are too long, they will overlap one another too far and cannot be welded down quickly enough. If too short, they hammer down too quickly to make a good job, and the weld will be thin.

If the scarfs are the right length and about the same size, which is important, the weld will finish down in good shape and make a smooth job, providing the ends are clean. When the pieces being heated, look as tho they are covered with grease, you may be sure the fire is dirty, or is too new.

A lap weld is sometimes made without scarfing the ends. For instance, pieces of 1? x 1/4 ? iron are to be welded by the lap method. They are brought to a welding heat without upsetting; taken to the anvil as previously explained for the scarf weld, lapped about ?/??-inch, as shown in Figure 30, and welded. This form of welding is used in a hurry-up job where there is no great amount of strain on the work. It is impossible to make a strong weld this way. Very thin stock, either iron or steel, can be welded to advantage in this manner by hammering on the flat sides. The edges, instead of being hammered, are cut off with a chisel, then ground or filed smooth. In welding very thin stock, a little flux is used. Always weld by separate heats, and do not rivet or split the stock to hold both ends in place. This is not necessary. Try to make the weld with one heat. All good welds are made in one heat.

For example, a piece like the one shown in Figure 31, is to be made by welding. The pieces should be prepared as shown in Figure 32. The square piece is 1? by 1? by 6?, the flat one 1 1/2 ? by 1/2 ? by 8?. The square piece is heated directly on one end. If the heat cannot be taken short enough, it may be cooled in water so as to upset it with a lip or projection, as shown. This lip can be worked out afterwards with a fuller, or it may be driven into a heading tool which has the top corners of the hole rounded. This will leave the corners of the lip round as shown. The bar at the end should also be made slightly convex, so that the center part comes in contact with the flat piece first. The flat piece is also upset in the center.

In welding, separate heats are taken. With the square bar, handled with the right hand, the pieces are brought to the anvil by the smith. The square bar is set on top of the flat one, and a helper strikes the top piece with the sledge, driving it down into the bottom one. The edge of the lip is then welded fast with a hand-hammer; or a fuller or set hammer is used, the helper striking with a sledge.

Iron may be welded by butting the ends together. In doing this, the bars must be long enough so that they can be handled without tongs. For instance, two bars of one-inch round stock, one five feet long and the other shorter are to be welded. This size is about as light as can be welded with this method. The ends are heated and upset a little making them a little high in the center so that when they are placed together, the contact is in the center. A short heat is taken on the end of each bar. The smith takes out the long bar and the helper the short one, butting the ends together on the anvil, as shown in Figure 33. The helper hammers on the end of the short piece with a heavy hammer while the smith holds the long one firmly, and hammers on the joint, at the same time turning the bar so as to hammer the joint all around. In welding heavier stock, a sledge should be used requiring more helpers. This method makes a good weld, providing the heats are clean.

Figure 34 shows a drawing of round stock prepared for a split weld. In making this weld, one piece is heated on the end, caught in a vise and split with a thin chisel. See Figure 35.

These prongs are then spread and scarfed on the inside with the ball of the hammer letting them become fan shape and as wide as possible. See Figure 36. The other piece is upset and both pieces are caught in the vise. The scarf is then hammered tight and the ends are cut so as not to have them too long. See Figure 37. The cutting of the scarf, and partly into the bar, helps to bind the pieces firmly while the heat is being taken. See drawing of piece ready to be welded, Figure 38.

A heat is now taken, using a little sand or welding flux, if the stock is very small. In welding, the first blow is struck on the end of the split piece to drive it down tight and weld it in the center. See Figure 39. The sides are next hammered to weld the laps. It is then finished. On heavy work, the heats are taken separately and placed on the anvil by the smith, in the same manner as described for a jump weld. Another form of split welding is shown in Figure 40. This method is used in welding heavy iron and steel, such as picks and drills. Notice the little beards cut with a chisel to help hold the pieces in position when heating. Heavy tool steel is also welded with this form of splitting. The first blow struck with the hammer on this weld, is on the end, forcing the pieces together; then on the flat part.

In Figure 41 is shown an angle made by welding on the corner; this is called a corner weld. It is generally made by using square or flat stock. Figure 42 shows the scarfs prepared for a corner weld, using 1? by 1/2 ? stock. The piece at "A" is scarfed with the ball of the hammer. The one at B, with the face of the hammer. Separate heats are taken and the pieces lapped and welded.

The scarfs for T-welds are made in just the same manner as for the corner weld, excepting that one scarf is in the center of the bar. See Figure 43.

In taking the pieces from the fire to the anvil, the one scarfed in the center is handled with the tongs in the left hand. The one scarfed on the end is handled with the right hand, letting it under the other, and then hammered. Notice how wide the scarf is made on the end piece at "A". This is done to cover the other scarf. All flat "T" scarfs are made in this manner.

Corner Weld--Brazing--Fagot Weld--Turning a Loose Eye--Hammock Hook--Finishing Wrought Iron--S Link--Welded Eye Pin.

A corner weld made by using heavy stock, for example, one and one-fourth inch square, is to have a square corner by welding. See Figure 44. With the dimensions six inches from one end, the bar is heated and cut about half thru from one side with a hot chisel. The bar is then heated and bent to about a right angle, as shown in Figure 45. A piece of 3/4 -in. square stock is cut on four sides as shown in Figure 46. This piece is welded into the corner as shown in Figure 47. The heat is separate, and the smith takes both pieces to the anvil when hot. He places them in position as shown in the drawing, the helper doing the welding. The long part of the bar is then broken off, another heat is taken and the corner is finished up by the smith.

Iron and steel can be fastened together by brazing. In doing this, the ends are tapered or dove-tailed together and bound with wire or a rivet to hold them in position. They are then placed in the fire and brought to a red heat. Some borax and spelter are put on and the heat is raised until the brass flows. The work is then taken out of the fire and let cool; then it is finished with a file, or by grinding. Spelter is an alloy of copper and zinc, and may be purchased from dealers. Brass wire may also be used in brazing, and sometimes copper.

In teaching boys forging, the writer feels that it is a waste of time to give a beginner little pieces to make, such as staples, hooks, etc. A boy cannot learn to handle his hammer, or to heat a piece of stock by making small things. What the beginner in forging needs is some work that he can swing a hammer on without danger of spoiling it. Very few boys on entering a shop can handle a hammer, and they certainly do not learn about heating metal in a forge, by working at staples, etc. The first exercise should be a fagot weld.

In doing this, two pieces of iron 1/2 in. square and 6 in. long are used. The instructor demonstrates the welding of these two pieces before the class. In making the weld, one piece is laid on top of the other and both are caught at one end with a pair of tongs. The tongs should fit the pieces nicely; a ring is placed over the ends of handles to bind the jaws firmly on to the pieces. A heat is then taken on about one-half of the length of the stock; the pieces are welded and at the same time drawn to 1/2 in. square. The pieces are now turned around in the tongs and the balance is heated and welded. While drawing stock always have the bar at right angles with the long side of the anvil. If the bar is not so held, it will twist on the slightly rounded face of the anvil.

There will be more or less iron burned by the boys in making this fagot weld; but this is necessary, for a boy can never learn how to work iron until he can heat it properly. He must over-heat and burn iron in order to understand the heat limitations of the metal.

After the weld is made and the bar is drawn to the original size, the ends must be squared by upsetting them. The bar when finished should be 1/2 in. square thruout its length, and straight with the ends squared.

It is then formed into a loose ring by hammering it over the horn of the anvil and not on a ring mandrel. In forming the ring, the ends are upset on an angle, so that when bent into ring form, they will fit together nicely. See Figure 48.

This exercise will be made in the same manner as number one, excepting that the bar is finished to ?/?? in. square, and a ring is turned on each end. See Figure 49.

The eye is formed by heating and hammering it over the horn of the anvil, giving it the shape as shown at B. It is then reheated, set on the horn of the anvil and hammered close to the eye as shown at C, which bends it central with the shank as shown at D.

In turning loose eyes of any size stock or dimensions, on the end of a bar, the ring is first turned into a circle of the desired size. It is then sprung central with the shank. With this method, no figuring of stock is required.

In making a hammock hook, the stock should be soft steel, which may be purchased for about the same price as iron. It will stand the bending strains better than iron. The size of the stock is 7 1/2 in. by 3/8 in. round. The end is heated and a loose eye formed. The other end is drawn to a taper with 1/4 in. of the end turned up as shown. See drawing of hook, Figure 50, and the different steps in forming the eye at A, B and C. The hook is formed over the horn of the anvil as shown in Figure 51. Figure 52 shows the finished hook with a dotted line drawn thru the center, indicating where the pull should come. In Figure 53 is shown a common fault when turning a loose ring at the end of a bar, in not bending the extreme end first. Notice Figure 54, where the end is bent as it should be.

The expert worker in iron is very careful not to hammer mark and destroy the section of a bar. One should remember that bending a ring or iron hook is simply holding the bar on the horn of the anvil and striking the part that protrudes past it. Never strike the bar when it is directly over the horn. This does not bend it, but makes a dent in the stock.

To finish wrought iron, all of the scale and dirt should be scraped off with an old file while the piece is hot. When the iron is cooled, linseed or machine oil is rubbed on. If the work is held over the smoke of the fire and then oiled, it will take on a darker color. Never paint iron work. This destroys the texture of the metal. Do not file work bright. It should be dark--filing is not forging.

Figure 55 shows a drawing of an S-Link, which is used to splice broken chains. In Figure 56 is shown he length and size of the stock. The ends are drawn to a short point and the center of the bar is marked with a center punch. One-half of the link is then formed, bringing the point at the center punch mark and using one-half of the bar. This is a simple link to make. The only thing to be careful about is to not destroy the section of the bar with hammer marks. This may be avoided if one does not strike the hook directly over the horn of the anvil, but to one side of the horn. See in Figure 57, the correct blow.

Figure 58 shows a drawing for a welded Eye Pin. The eye may be made any size for practice. In making the ring, the bar is heated in the center and hammered over the outer edge of the anvil, as shown in Figure 59. The piece is now turned end for end, and jogged down again with the ball of the hammer. See Figure 60. The piece should now look like the drawing in Figure 61. The center of the piece is heated and hammered over the horn of the anvil to make the ring round and to bring the shanks together. See Figure 62.

In welding, the piece is caught by the ring with a flat pair of tongs. See Figure 63. It is now placed in the fire so as to get the heat close to the ring. The tongs are then removed, until the piece reaches a white heat; the piece is again caught with the tongs, and the heat is raised. It is taken out and set on the edge of the anvil and hammered as shown in Figure 64. The first blow struck is close to the ring in order to weld that part first. If it cannot be all welded in one heat, it should be reheated at once. Do not hammer unless the heat is a welding heat, as the stock will become too thin before it is welded. Do not heat the tongs red as this destroys them and the piece cannot be held with hot tongs. When the ring is welded, the end is drawn to a square point. See Figure 65.

Staples--Open Links--Welded Chain Links--Punching--A Grab Hook.

Staples are used for hasps, gate hooks, and for various other purposes. They are made from all sizes of stock, depending on the use to which they are put. On account of its pliability, soft steel is the best stock to use in making staples.

The length to cut stock is shown in the drawing of the staple in Figure 66. The stock is caught at one end with a pair of light tongs. The piece is then heated and drawn out to a point; it is reversed in the tongs and the other end is drawn out. The center of the piece is then reheated and bent into shape over the horn of the anvil.

In drawing any piece of stock to a tapered point, the taper should not be hammered on one side continuously and, when turned over, hammered back again. To have a taper on all four sides alike, the bar must be raised the proper distance and not laid flat on the anvil. Figure 67 illustrates the wrong way and Figure 68, the correct way.

In Figure 69 is shown a drawing of an open link. Open links are used in the splicing of broken chains. In splicing a chain, the link is opened by driving a chisel between the laps, or it is opened when made. These laps are hooked into links of broken chain and then driven together. In making the link, one end is drawn to a flat point and a hook is hammered on it. See Figure 70. The other end is heated and drawn out as in Figure 71. The center of the piece is now heated and bent over the horn of the anvil to the desired shape. See Figure 72. Notice in the drawing that the hooks at the open end of the link are not very long. They should not be made longer than shown.

The form and length of the stock for this exercise is shown in Figure 73. The link may be made from iron or soft steel. After the stock is cut, it is heated in the center and bent over the horn of the anvil into a "U" shape. See Figure 74. The ends are now heated and scarfed by setting them on the anvil as shown in Figure 75. The iron is then struck on top with the hand hammer. After each blow, it is moved away from the anvil just a little, giving the end a bevel, so that, when finished, the scarf consists of a series of slanting notches.

In scarfing, both ends of the links are set on the anvil. The end of the one on the right hand side must not be moved when scarfing the other. After each blow of the hammer, the piece is moved just a little. If it is moved too far and the other end of the link is fixed it will describe an arc. See Figure 76. This is the method used in scarfing links. Sometimes they are welded without scarfing, but it is not good practice.

Figure 77 shows the link scarfed, lapped and ready to be welded. In welding, the heat is taken directly on the end of the lap and not on the sides, so as not to burn the stock above the laps. When the link has the welding heat, it is taken to the anvil and hammered on the flat sides, then set on the horn of the anvil, and hammered on the corners. See Figure 78. The shape of the link at the weld should be just a little pointed for a strong link.

In making chains, do not weld two single links and then one between them. Weld a link on the end of the chain and keep repeating until finished.

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