Fagot-welding was much practiced by the smith in times past. When one’piece of iron is not large enough for the work, two or more pieces are laid on top of each other and welded together. Sometimes many small pieces are put up in a bundle, and held together with wire. It was claimed by the old-time gunsmith that a gun barrel made from old horse shoes, or, better yet, from old horse nails, would make the best gun. In such a case, these pieces were fagot-welded. We do very little of that kind of welding now. If the size we have on hand is not large enough, we send for the right dimension.
The lap-weld is the most used, and it is also the easiest and the strongest weld, if it is properly done.
The first thing to do in preparing for a lap-weld is to upset the ends to be lap-welded. The upsetting can be done in different ways,—either by hammering the stock back, in preparing the lap (see Fig. 9), or by butting the end of the iron against the anvil. The material should be a good deal heavier over and behind the lap before it is welded than what it is to be when welded. If the pieces are simply scarfed without upsetting, it will make a weak weld, and a meager looking weld; for the stock will then be smaller over the weld than in the rest of the bar, and that is just the kind of welds every new beginner makes. It is always the safest to have plenty of stock for the lap; for if it is, the weld can be forged down so that it is impossible to detect the place of the weld. This can be done only where there is material enough.
The scarf should be made convex, not concave; if the scarf is concave, there will be scales or cinders and. air in the pocket formed, and there will never be a solid, strong weld. See Fig. 10.
In placing the iron on the anvil for the weld, let the apprentice hold his piece so that the extreme end does not come in contact with the anvil, and the smith should rest his piece over the opposite corner of the anvil, so as to guide it in placing his piece in position over the other; for it is not so easy to place this piece right, and if it is not placed right, and let down on the other, where it is liable to stick, it will be almost impossible to get it loose and replace it before the weld is too cold. See Fig. 10.
It is difficult to teach how to find the proper welding heat in any other way than by an object lesson, and then the apprentice must be humiliated by many failures before he is able to make a good weld.
In all lap-welds the ends must be scarfed,—that is, pointed to a sharp edge,—in order to get a strong weld. In cheap blacksmithing and such light work as hub rings, etc., the weld is often taken without the scarfing; but in every case when this is done you will find that the square ends will cut into the stock, and weaken the weld considerably. You may be able to do cheap work that way, but not good work.
The butt-weld, although not the strongest, is often a very convenient weld. In this weld, the pieces are butted together without scarfing. It comes handiest in heavy round material, and the ends are rounded, as shown in Fig. 12. If the ends are convex when welded, the weld will start in the center, and force any foreign matter out. On the other hand, if the ends are concave, it will form a pocket where cinders, scales, and gas will form, and a good strong weld is then impossible.
If the bars are long enough, the weld is most easily taken in the fire; that is, it is started while the bars are in the fire. The helper holds one end with a sledge up against the end of the bar, while the smith holds the other end from the opposite side of the forge, and strikes with a heavy hammer on the end. When the weld is sufficiently forced together, the bar is taken out and placed on the anvil, where it is forged down and smoothed up. In a butt weld there is a deep seam where the ends meet, and the ends must be upset so much in welding that there will be material enough to work down on and smooth the weld. If the pieces are short, they must be welded out of the fire, standing the ends in an upright position.
The jump-weld is simply another form of the butt-weld. This weld should not be resorted to by any but an experienced smith, for it is a very difficult weld to make, and, if not properly made, will prove of little value. The bar welded to a flat or wider piece should be upset till it flares out in a flange-like shape; and the wider the flange or foot, the better. When both pieces have the proper heat, strike on the end of the bar a few blows; then finish up with the fuller,—not the set hammer as some third-class smiths do; for the set hammer has sharp corners, and will spoil both the looks and the strength if it is used here. Let me say in this connection that the set hammer should be used sparingly in all forging. The fuller is in most cases the better tool.
T-weld is another form of the butt-weld, and is also a difficult weld, comparatively. Still this weld is easily mastered. When the T is to be from flat iron, scarf the bar on the edge where the weld is to be, and the other bar is to be scarfed on the end. This is the weld used on our “fill iron.” See Fig. 14. If the T is to be made of round or square material, scarf and prepare as in Fig. 15. In Fig. 14, No. 1 is placed on top of No. 2 as far as the dotted lines indicate. In Fig. 15 the one end is grooved over the horn of the anvil, and the other is upset over the point where the T is to be welded.
In thin stock, it is often difficult for a less clever welder to weld the pieces together, and in such a case a split weld, like Fig. 16, can be made. This is the weld all third-rate smiths use in welding tire, but no experienced tire welder will ever resort to such a method. For heavy stock, especially in highly carbonized steel, a split weld is the best. In preparing the iron or steel bars to be welded by this method, proceed as follows: First upset the pointed end, and prepare as is shown in Fig. 17. You will notice some notches in the scarfed point. Then cool this piece off. Next prepare the split end by upsetting, either before it is split or after, by fullering it in the fork. Now heat the forked end quite hot, but leave the pointed end cold. By so doing, the cold prongs in the pointed end will penetrate into the hot ends of the forked end, and hook the pieces together, so that it can be handled in any shape or manner, and they will not come apart. In closing up the fork, have the helper strike hard blows with a twelve pounder. If there should be any crevices at the point of the inside end, as there is liable to be, make a wedge and drive it in to fill this hole; for if any little crack is left open, cinders are liable to be blown in between, and spoil the weld. Next prepare to weld. Have a clean and large enough fire, and heat slowly, for the inner piece will not heat so fast as the outside. If steel, be careful not to burn the outside lips. Have a light hammer with a long handle to “stick” the lips in the fire with; that is, the thin ends of the forked end should be welded while the piece is yet in the fire. Then place on the anvil, and let one or two helpers come down on it with a heavy sledge.
Angle-weld is one of the easiest welds to make. Simply pene out the corners as shown in A in Fig. 18. The leg B should be pened out the same way. Place A on top of B, and weld. When a piece of angle iron is wanted this is the quickest and strongest way to make one.
Suppose a band is wanted around a round object, the diameter being six inches, and the stock to be half an inch thick. To find the length required to bend anything when the stock is not over one-half inch thick in the band, multiply the diameter by 3, and add three thicknesses of iron which is taken up in bending and one thickness for the weld. That is, to band an object six inches in diameter with half-inch thick iron,
In bending a band, it will be observed that the inner side of the curve is shortened or upset, while the outer side is stretched and is consequently a little longer.