Editing Blacksmith (section)

==Smithing process==
[[File:T1.-Ferrer (26049209744).jpg|thumb|339x339px|Smithing process in Mediterranean environment, [[Valencian Museum of Ethnology]]]]

Blacksmiths work by heating pieces of wrought iron or steel until the metal becomes soft enough for shaping with hand tools, such as a hammer, an [[anvil]] and a [[chisel]]. Heating generally takes place in a [[forge]] fueled by propane, natural gas, coal, charcoal, [[coke (fuel)|coke]], or oil.

Some modern blacksmiths may also employ an [[Oxy-fuel welding and cutting|oxyacetylene]] or similar [[blowlamp|blowtorch]] for more localized heating. [[Induction heating]] methods are gaining popularity among modern blacksmiths.

Color is important for indicating the temperature and workability of the metal. As iron heats to higher temperatures, it first [[black-body radiation|glows]] red, then orange, yellow, and finally white. The ideal heat for most forging is the bright yellow-orange color that indicates ''forging heat''. Because they must be able to see the glowing color of the metal, some blacksmiths work in dim, low-light conditions, but most work in well-lit conditions. The key is to have consistent lighting, but not too bright. Direct sunlight obscures the colors.

The techniques of [[smithing]] can be roughly divided into forging (sometimes called "sculpting"), welding, heat-treating, and finishing.

===Forging===
[[File:Acampamento Farroupilha, Parque da Harmonia, Porto Alegre, Brasil 2015 17.webm|thumb|right|A blacksmith hand-forging a tool during the [[Acampamento Farroupilha]] event in [[Porto Alegre]], [[Brazil]], 2015.]]
[[File:01 Forgeron 08.jpg|alt=Picture of a blacksmith|thumb|A blacksmith]]
[[Forging]]—the process smiths use to shape metal by hammering—differs from machining in that forging does not remove material. Instead, the smith hammers the iron into shape. Even punching and cutting operations (except when trimming waste) by smiths usually re-arrange metal around the hole, rather than drilling it out as [[swarf]].

Forging uses seven basic operations or techniques:

* Drawing down
* Shrinking (a type of upsetting)
* Bending
* Upsetting
* [[Swaging]]
* Punching
* Forge welding

These operations generally require at least a hammer and [[anvil]], but smiths also use other tools and techniques to accommodate odd-sized or repetitive jobs.

====Drawing====
[[File:AngelAguilarOcotlan3.JPG|thumb|Blacksmith [[Apolinar Aguilar Velasco|Apolinar Aguilar]] at the furnace of his blade workshop in [[Ocotlán de Morelos|Ocotlan de Morelos]], Oaxaca, Mexico]]
Drawing lengthens the metal by reducing one or both of the other two dimensions. As the depth is reduced, or the width narrowed, the piece is lengthened or "drawn out."

As an example of drawing, a smith making a chisel might flatten a square bar of steel, lengthening the metal, reducing its depth but keeping its width consistent.

Drawing does not have to be uniform. A taper can result as in making a wedge or a woodworking chisel blade. If tapered in two dimensions, a point results.

Drawing can be accomplished with a variety of tools and methods. Two typical methods using only hammer and anvil would be hammering on the anvil horn, and hammering on the anvil face using the cross peen of a hammer.

Another method for drawing is to use a tool called a [[Fuller (metalworking)|fuller]], or the peen of the hammer, to hasten the drawing out of a thick piece of metal. (The technique is called fullering from the tool.) Fullering consists of hammering a series of indentations with corresponding ridges, perpendicular to the long section of the piece being drawn.  The resulting effect looks somewhat like waves along the top of the piece.  Then the smith turns the hammer over to use the flat face to hammer the tops of the ridges down level with the bottoms of the indentations. This forces the metal to grow in length (and width if left unchecked) much faster than just hammering with the flat face of the hammer.

=== Bending ===
[[File:Ministry of Information First World War Official Collection Q30985.jpg|thumb|A [[horseshoe]] being bent into shape]]
Heating iron to a "forging heat" allows bending as if it were a soft, [[ductile]] metal, like copper or silver.

Bending can be done with the hammer over the horn or edge of the anvil or by inserting a bending fork into the [[hardy hole]] (the square hole in the top of the anvil), placing the work piece between the tines of the fork, and bending the material to the desired angle. Bends can be dressed and tightened, or widened, by hammering them over the appropriately shaped part of the anvil.

Some metals are "hot short", meaning they lose their tensile strength when heated. They become like [[Plasticine]]: although they may still be manipulated by squeezing, an attempt to stretch them, even by bending or twisting, is likely to have them crack and break apart. This is a problem for some blade-making steels, which must be worked carefully to avoid developing hidden cracks that would cause failure in the future. Though rarely hand-worked, [[titanium]] is notably hot short. Even such common smithing processes as decoratively twisting a bar are impossible with it.

=== Upsetting ===
Upsetting is the process of making metal thicker in one dimension through shortening in the other. One form is to heat the end of a rod and then hammer on it as one would drive a nail: the rod gets shorter, and the hot part widens. An alternative to hammering on the hot end is to place the hot end on the anvil and hammer on the cold end.

=== Punching ===
Punching may be done to create a decorative pattern, or to make a hole. For example, in preparation for making a hammerhead, a smith would punch a hole in a heavy bar or rod for the hammer handle. Punching is not limited to depressions and holes. It also includes cutting, slitting, and drifting—all done with a chisel.

==== Combining processes ====
The five basic forging processes are often combined to produce and refine the shapes necessary for finished products. For example, to fashion a cross-peen hammer head, a smith would start with a bar roughly the diameter of the hammer face: the handle hole would be punched and drifted (widened by inserting or passing a larger tool through it), the head would be cut (punched, but with a wedge), the peen would be drawn to a wedge, and the face would be dressed by upsetting.

As with making a chisel, since it is lengthened by drawing it would also tend to spread in width. A smith would therefore frequently turn the chisel-to-be on its side and hammer it back down—upsetting it—to check the spread and keep the metal at the correct width.

Or, if a smith needed to put a 90-degree bend in a bar and wanted a sharp corner on the outside of the bend, they would begin by hammering an unsupported end to make the curved bend. Then, to "fatten up" the outside radius of the bend, one or both arms of the bend would need to be pushed back to fill the outer radius of the curve. So they would hammer the ends of the stock down into the bend, 'upsetting' it at the point of the bend. They would then dress the bend by drawing the sides of the bend to keep the correct thickness. The hammering would continue—upsetting and then drawing—until the curve had been properly shaped. In the primary operation was the bend, but the drawing and upsetting are done to refine the shape.

=== Welding ===
[[Welding]] is the joining of the same or similar kind of metal.
[[File:Mendel II 072 r.jpg|thumb|Blacksmith, 1606]]
A modern blacksmith has a range of options and tools to accomplish this. The basic types of welding commonly employed in a modern workshop include traditional [[forge welding]] as well as modern methods, including oxyacetylene and [[arc welding]].

In forge welding, the pieces to join are heated to what is generally referred to as ''welding heat''. For mild steel most smiths judge this temperature by color: the metal glows an intense yellow or white. At this temperature the steel is near molten.

Any foreign material in the weld, such as the oxides or "scale" that typically form in the fire, can weaken it and cause it to fail. Thus the mating surfaces to be joined must be kept clean. To this end a smith makes sure the fire is a reducing fire: a fire where, at the heart, there is a great deal of heat and very little oxygen. The smith also carefully shapes mating faces so that as they come together foreign material squeezes out as the metal is joined. To clean the faces, protect them from oxidation, and provide a medium to carry foreign material out of the weld, the smith sometimes uses flux—typically powdered borax, silica sand, or both.

The smith first cleans parts to be joined with a wire brush, then puts them in the fire to heat. With a mix of drawing and upsetting the smith shapes the faces so that when finally brought together, the center of the weld connects first and the connection spreads outward under the hammer blows, pushing out the flux (if used) and foreign material.
[[File:3 tourist helping artist blacksmith in finland.JPG|thumb|left|An artist blacksmith and a striker working as one]]

The dressed metal goes back in the fire, is brought near to welding heat, removed from the fire, and brushed. Flux is sometimes applied, which prevents oxygen from reaching and burning the metal during forging, and it is returned to the fire. The smith now watches carefully to avoid overheating the metal. There is some challenge to this because, to see the color of the metal, the smith must remove it from the fire—exposing it to air, which can rapidly oxidize it. So the smith might probe into the fire with a bit of steel wire, prodding lightly at the mating faces. When the end of the wire sticks on to the metal, it is at the right temperature (a small weld forms where the wire touches the mating face, so it sticks). The smith commonly places the metal in the fire so he can see it without letting surrounding air contact the surface. (Note that smiths don't always use flux, especially in the UK.)
Now the smith moves with rapid purpose, quickly taking the metal from the fire to the anvil and bringing the mating faces together. A few light hammer taps bring the mating faces into complete contact and squeeze out the flux—and finally, the smith returns the work to the fire. The weld begins with the taps, but often the joint is weak and incomplete, so the smith reheats the joint to welding temperature and works the weld with light blows to "set" the weld and finally to dress it to the shape.

=== Finishing ===
[[File:Australian blacksmith.jpg|thumb|A blacksmith at work]]

Depending on the intended use of the piece, a blacksmith may finish it in a number of ways:

* A simple jig (a tool) that the smith might only use a few times in the shop may get the minimum of finishing—a rap on the anvil to break off scale and a brushing with a wire brush.
* Files bring a piece to final shape, removing burrs and sharp edges, and smoothing the surface.
* [[Heat treatment]] and [[case-hardening]] achieve the desired hardness.
* The wire brush—as a hand tool or power tool—can further smooth, brighten, and polish surfaces.
* Grinding stones, abrasive paper, and emery wheels can further shape, smooth, and polish the surface.

A range of treatments and finishes can inhibit oxidation and enhance or change the appearance of the piece. An experienced smith selects the finish based on the metal and on the intended use of the item. Finishes include (among others): paint, varnish, [[Bluing (steel)|bluing]], [[Bluing (steel)|browning]], oil, and wax.