, or the art of smiting black metals
is the art of taking iron ore
and forming it into a usable implement
Black metals refers to those metals which were not particularly pretty, ie: not gold, silver, etc... The best guesses put the origination of blacksmithing somewhere around the Caucasus(*3). the art quickly spread across Europe and into Asia, India, etc. one can imagine how quickly it must have spread given the relative abundance of iron ore across the world as well as the higher quality of tool and weapon that could be produced.
First a short discussion of the materials involved.
The original smith would probobly have done his own smelting/refining of the raw iron ore. When iron is found in it’s natural form it often has many impurities in it as well as many other minerals or metals. When the iron is smelted using a blast furnace it is put in what is known as a crucible and heated till it melts. The impurities then float to the top and may be skimmed off and thus removed from the metal. The then purified iron is poured into molds to form usually rectangular ingots, or cylindrical bars (or triangular bars 8ft in length called “sluts” but this was a mostly french habit). This type of iron was known as “cast iron” by virtue of the casting process used to make it. Cast iron was improved and turned into what is known as “wrought iron” by a process or resmelting the metal and pounding out any more impurities that were left from the skim job performed on the cast iron, as well as burning out any excess carbon in the iron. This was still an inexact science which meant that depending on how everything went during the process of resmelting one could get a number of different results. Such as: cast iron(again) which contained more than 2.2% carbon and was not usable for working, wrought iron, which contained a carbon content of .3% or less and was the type of iron used most for farm implements, nails, door hinges, and every day type things. Another possible result was steel, which had a carbon content from .3%-2.2%. This metal was most used for making tools, weapons, springs. The reason that it was used for these items specifically was because of the ability to harden, or temper the steel by heating then quenching in water, i’ll discuss that a bit more later.
As smithing of iron became more prevalent this task was often overtaken by individuals, or companies, whose entire purpose was the smelting of iron(*1). This freed the smith up to do more in the field of production.
Steel is a derivative of iron differing only in the carbon content. Pure iron has no carbon at all, where as steel is simply iron with a carbon content. Initially steel was made using a terribly crude method. Pure iron bars were packed in a box of carbon dust which was heated till the iron bar was white hot. The bar was then kept at a stable temperature for a number of hours depending on the size of the bar. This of course led to uneven carbon contents throughout the metal bar, ranging anywhere from 0.3-percent to 2.2-percent carbon. The uneven and haphazard method for steel production created metal that could be tempered but often tempered unevenly causing parts of a knife to dull faster than others on the cutting edge and other such problems.
In 1860 a new technique of iron refining was developed which created a type of metal called “mild steel” which wasn’t actually steel at all but iron which was slagless and free of impurities. Though it has a small carbon content it cannot be tempered. Mild steel doesn’t have a fibrous structure as wrought iron does allowing it to be bent to more acute angles as well as allowing for holes to be punched through it with minimal difficulty. The downsides were that it did not weld easily, it’s welding temperature was just below that of it’s burning temperature. The use of flux during welding is absolutely essential when working with mild steel.
The tools of the trade.
The tools the blacksmith uses are relatvely simple, and most may be made by the smith himself. The hammer is the tool used to work the steel/iron. There are a massive amount of hammer types available to the smith and many may be used on a single job. Hammers names are derived from the type of face they have. The hammer most familiar to the weekend warrior or amateur woodworker is what’s called a claw hammer and is rarely if ever used in blacksmithing. Most of the hammers used in smithing are peen hammers, ie: ball peen, cross peen, etc... These hammers have faces that are designed for striking the metal in a specific way. The sledge hammer is also used, though mostly for rough shaping , or for folding and welding metal together (see pattern welding, or japenese sword making for good examples)
The anvil in it’s simplest form is a large piece of iron with a flat surface to work metal upon. The most common anvil used was the design that you're probably familiar with from seeing it dropped on various anthropomorphic cartoon animals heads. This design incorporates a flat working surface (the top) as well as what’s called the “horn” that would be the protrusion from one of the sides. The horn is used when a curve must be put into metal or when a curved surface is needed for forming a piece of metal, think wagon rims, and helmets. Some anvils featured a square hole on the top of the anvil on the opposite end from the horn. This hole is called a “hardy hole” it’s used when striking a whole through a piece of metal so that one doesn’t scrape or dent the working surface of the anvil. There are also a number of inserts that can be placed into the hardy hole to fill a specific need. Anvils are generally very heavy, being designed that way to keep them from bouncing around when struck. As well as to give them a good solid mass to hit against when working, as something of smaller mass might not stand up to the stresses of heavy repeated blows from hard metal objects.
Tongs are used for manipulating metal. When metal is heated it’s generally not pleasant to handle (although iron/steel don’t conduct heat very well, meaning if the bar is long enough one may handle the cold end bare handed with little worry, not something copper or bronze smiths could do!). Tongs come in a variety of ends designed for special purposes: flat ends (picking up square stock or sheet), round ends (for bar stock), some had 90 degree bends to facilitate handling of wheel rims. The production of tongs was a very easy process and smiths would usually make their own set during their apprenticeship. Often specific tongs would be created for a special job and never used again.
Chisels and punches
A blacksmith also had two types of chisel sets, a cold set and a hot set. Due to the differing properties of metal depending on wether it’s hot or cold the two sets were developed. One for use while the metal was heated, one for using while the metal was cold. These same rules applied to punches as well.
Due to the large number of forge designs i’m only going to cover the basics of “forge physics”. A forge consists of a hearth of some sort, bellows, and a tuyere (pronounced “tweer”). The hearth was where the material to be burned (charcoal/coal, though some modern forges use gas) was placed. Below the hearth was the tuyere, which in it’s simplest form was simply a passage for air into the bottom of the hearth. The bellows are a device used to push air, you might have a pair by your fireplace. If you don’t know what the bellows are remember those anthropomorphic cartoon animals we discussed earlier? Remember when one was crushed by the anvil, how they would stick this thing into his mouth that somewhat resembled an accordion and would pump him up back into “3D”. Those are bellows being used to inflate the character(*2).
When up and running the hearth contains some sort of fuel which is burning, the bellows are used to force air up and through the burning material, thus increasing the temperature. Here’s a simple equation to put it all in perspective: fire+air= bigger fire
The blacksmith then takes his metal and puts it in the hearth. He then waits till it arrives at his desired working temperature at which time it is removed from the forge and transferred to the anvil where it is worked until it’s lost to much heat. The metal is then returned to the forgeand heated back up to working temperature. Rinse lather repeat...
When the desired shape and form have been achieved the metal is allowed to cool (or is quenched depending on what’s being made, what type of metal etc...). If the item in question is made of steel and needs to be hardened the steel is brought up to the appropriate heat then quickly dunked in a vat of water, brine (salt water), or sometimes motor oil. This process was called quenching and caused the steel to become very hard and brittle. The different quenching mediums are used to quench the metal at various speeds. Since quenching is really just dissipating heat quickly water will quench faster than brine which will quench faster than the motor oil. When the steel is cooled it is usually very brittle and relatively useless in this form. So the steel is reheated again then allowed to slowly cool down on its own, this is called annealing. Annealing allows the molecular structure of the metal to relax and expand comfortably, this reduces the brittleness of the metal as well as allowing any particularly tight spots of contracted metal to loosen up. The steel is then heated one last time, not as hot as the first time though, and quenched once more. This last quenching allows the steel to tighten up in it’s relaxed form, thus regaining it’s toughness without losing all it’s flexability.
When finally cooled if it’s a bladed object that has been made, the blades are sharpened by grinding down the cutting edge till it’s sharp.
That, in more words than were probably needed, is the basic method of blacksmithing used world wide for the better part of human history.
(*1) An exception to this rule would be the smiths of Japan. Traditionally when a Japanese sword smith would go to make a sword, he would collect the iron by dragging a lodestone (magnet) across a beach and then scrape off the iron that was picked up. He would then smelt this himself. That is not to say this is the way all Japanese sword smiths worked, as that would make for terribly slow sword production, there were independent smelting companies of course. This was simply an anecdote citing a specific tradition of the smith smelting his own iron.
(*2) i’m beginning to think i should have titled this node “all i know about blacksmithing i learned from cartoons.”
(*3) Auduster points out "The current thinking is that Iron smelting originated in the Balkans, not The Caucasus.. But this is still speculative"