Sunday, 8 December 2013

Novgorod Hook Knife

A short while ago I was asked to produce a replica of this artefact (bottom of image), found at the famous excavations at Novgorod, Russia.  The digs there have brought a huge wealth of objects forward detailing ordinary life, wealth and belief in the city between 10th and 15th centuries.
These finds are so important, as we tend to focus on marshal aspects of society when we look back at those times. Shiny things, gold items, swords and crowns usually capture the eye, but to me these humble objects are of equal value.
 It’s also fascinating to me how little these ordinary objects are unchanged by time. A successful design was realised early on and remained as such until the 20th century where many regions of Europe still made wooden table ware commonly.
All I had to work from was the image shown and by best judgment and understanding of materials and methods of the time.
Until the modern era, hardenable edge steel was a metal of value approaching that of silver and as such was used sparingly.  The reason for its value was the amount of labour involved in its manufacture, with many ^hours^ between quarrying the ore, smelting, carburisation and refinement. All of which was undertaken, of course, by hand. All fuelled by charcoal which its self was felled, coaled and transported etc. So we can see that in the same way as modern commerce, trade and commodity were costly endeavours and this was reflected in the final product.
To make the steel “go further”, blacksmiths, weapon makers and tool smiths would use cunning methods of forgewelding steel onto simpler, cheaper “wrought iron” like materials.   
With these pressures on the historic blacksmith in mind, I forged this blade with the same ethos using some “shear steel” ( wrought iron that has been worked and re worked to expel excess amounts of silica but also held at high temperature for sustained periods in a container packed tightly with a carbon rich material such as charcoal or hoof. At these high temperatures, the carbon diffuses in to the iron, allowing it eventually to be hardened when quenched.) And wrought iron (the ubiquitous blacksmith material, until the mid 20th century.  Wrought contains low amounts of carbon, sulphur, silica and some other alloying elements all of which enter the metal when it is smelted with coal. It has been called a crude material for it tendency to split when worked at lower temperatures, but I find it very evocative to work with as its low carbon content makes it incredibly smooth and soft to forge. It also has a distinctive smell. At high temperatures, the silica liquefies and is expelled with each hammer stroke but it also has interesting values as a fluxing agent, assisting with forgewelding.).
Both of these pieces of material are themselves considerably old. The shear steel was found by a friend when metal detecting on his land and is an old file- when files ceased being made from shear, I cant tell you but I know they were commonly made from “cast steel” (an early, homogenised low silica carbon steel) from the mid 19th c, so its my assumption that the file predates that era, by how much, I couldn’t say. The piece of wrought is salvage from a derelict railing, also 19th century.
Interesting point for all you metal smiths out there, wrought iron that is round stock was generally of much higher refinement than square stock from the same time. This was because lower quality iron would have been ripped apart when passed through the rollers. So, if you have a choice between round and square, use the square for your etched, gnarly blades and the round for fine forging on restoration jobs.
The first job was to “knock down” the pieces to a similar size so that they could be joined together, I also had to fold and weld the shear steel to itself.
The billet of shear was crimped over at the end to allow the wrought to be inserted and welded together. I’ve seen this kind of weld prep illustrated in how they used to “steel” chisels.  It was satisfying to use no other joining methods than this.

Iron inside, wrapped in shear steel.
Once the steel was fully welded, the “tang” was drawn down and folded over to cover the first weld seam and welded again. This drew the steel into the core of the tang adding an amount of spring and resilience once the blade was hardened.
The steeled “blade” is in the tongs, the tang being welded.

Once the piece was forged out, a first grind was done to establish the bevel, exposing the steel on the edge but leaving the Iron on the “top” of the blade. After the grind, the blade was shaped over the anvil a little more grinding and finally hardened.

You can see the steel edge revealed here.
The shear steel took a good hardness, so I sharpened the tool and gave it a light etch to reveal the construction in the blade.

I should also mention that the tool is left handed.
This was an interesting project and so enjoyable to use the ancient materials.