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.

Thursday, 14 November 2013

Large Bearded Axe

A friend came by the workshop a short time ago to look at collect a froe and a hook knife, we also discussed making an axe- something about a kilo, double bevelled and bearded.

At around the same time, this video did the rounds on Facebook showing a wonderful axe forge in Maine. If you care about our lost industrial heritage or the skill the human is capable of do yourself a favour and watch this video. Take a moment to meditate on the thought that that firm shown represented not only their endeavours and experimentations in tool making, but actually the culmination of two and a half thousand years of research, material and process development.

 There is an old anecdote that I will paraphrase (butcher) here, which perhaps hints at what I’m trying to say.

“A person enters a workshop and watches a potter/blacksmith/carpenter making a beautiful bowl/scroll/joint and says

 “Wow, that was incredible- how long did that take you? Ten minutes? Half an hour?

The maker responds

 “20 years”. 

The point is that in craft, every single movement and action is the product of all the maker’s combined experiences leading up to that moment. Whilst someone could learn the same task in a day they would not be able to understand and implement it with the same nuance as the time served craftsperson.

In a similar way, the traditional crafts are building not only on your own experience but also your craft forbears and thus-

“How long did that axe take?”

 “Two and a half thousand years”

  One of the many interesting details of this video was how they were “steeling” the edge of their axes with a horseshoe shaped bit, wrapping around the softer iron body. I had read about this technique and seen it illustrated before but actually seeing it implemented inspired me try this method out as an experiment.

So, we begin with a piece of steel.


The start weight was around a kilo, I was expecting some loss from forging and grinding, but also we would be adding weight with the steel edge.

This initial piece was forged and “upset” to form this "L" shaped piece.
The edge steel was forged to give this cross section

The body of the axe was cleaned and the edge rounded to present a better face for welding.


The edge steel was formed into the “u” shaped stock that mated well with the mild steel body.


The two pieces were brought together and fitted tightly before being brought to higher temp and having flux applied before the final welding phase could begin.


And now an apology…..

I forgot my camera! So there are no pictures of the middle moments where the eye is formed using the “asymmetric method” and forge-welded together. So yes, sorry about that.
Must. Try. Harder.
The best I can offer is this image of the body before the eye was formed, showing where I was going to divide the stock up.
And then suddenly……

So this is where we arrived- something hefty at about 1100 grams with a true razor for its 7 inch edge and a neat beard.
Regards the “overlay” method for the edge- I found it easier to implement once the stock was prepared. I will think more about this on following tools.
Thanks for looking.



Sunday, 27 October 2013

Hook Knives

 These rather strange looking curved blades were nearly an extinct tool until the recent renaissance in green- wood working.  The wooden table ware (called “Treen”) that they are instrumental in producing has been ubiquitous throughout Europe for millennia, only in recent decades has industrial process allowed ceramic bowls and plates to become truly commonplace at the table. That said, as recently as the 1950’s and 60’s there were still regions of the UK where the Turners could still be found producing green wood wares for everyday use and more commonly on the continent.

The knives appear, outwardly, to be a simple thing- a bent, single edged blade- however when one sets about to use and make them their hidden complexity becomes apparent…

The difference between a hook knife being a pleasure and a pain to use is subtle and nuanced, a matter of Geometry and attention to detail.

Firstly, the blade blanks are forged. The steel I am using here contains between 1.1 and 1.2% carbon.

The first point of interest that we come across is that in order for the inside of the blade to be flat on the finished, curved knife, they must first be hollow-ground whilst the piece is still straight.  This is because the inside of the knife will be compressed when it is bent- making the interior cross section convex, if the forged-in flatness was left uncorrected.


Additionally, the blunt edge must be ground to a radius that doesn’t interfere with the curving cut, this again is done when the blade is straight.

The bevel at the edge is also partially ground at this point as it would be close to impossible to grind one evenly once the piece is curved. If it is left too thick, it will more difficult to sharpen after hardening as it will be… well, hard. If it is too thinly ground, the edge can be easily overheated causing the steel to lose carbon and thus making it harden less effectively.

These different shapes can be seen together in cross section.

After this first grinding phase the work is reheated and the initial, acute bend in the ricasso (blunt) area is put and the curve is delicately put in either around a former for the consistently radius “twca cam” style traditional knife or freehand for the modern, versatile “compound” hook.  Care being taken not to damage the ground in cross section, which could be easily done whilst the metal is soft.
Twca Cam blades

Once hardened they are tempered for an hour to relieve the brittleness and then ground sharp. This is tricky because each blade must be continuously moved to keep the grind smooth and even. The blades are sharpened and polished with a high grit buffing compound, leaving a mirror finish.
After final sharpening I give each blade its second temper for an hour to ensure it is fully stress relieved and at it’s most resilient.
The tempering process causes a range of oxide colours to form on the steel surface, these colours precisely indicate temperature. This golden colour, whilst permanent is exactly one molecule thick and so, easily removed with a gentle stropping- it is, though, very beautiful and as such I have been leaving it in place as a proof and a decoration.

These knives are an interesting thing to make and ive been very satisfied with how well they cut.

Please contact me either on my Facebook page or by leaving a comment here


Friday, 25 October 2013

Bespoke carving axe

I had the pleasure of forging an ultra-lightweight carving axe for a customer this week, coming in at about 550g.

These smaller axes are such a joy to forge – they are condensed essence of axe.

This one has a forge welded bit and a mild steel body, the eye was hot punched.
I started with a short piece of 20 x 40mm mild steel

This was then upset before the edge was split, and a tapering carbon steel insert was inserted

This was edge piece inserted hot, set and then forge welded by hand

The eye was hot punched and drifted, the edge for was refined, and everything was straightened up.

 Once forging is completed, the piece was heated one more time and allowed to cool naturally to relieve stress- this is called “normalising” and is the first phase of the heat treatment. After this cycle, the edge is ground to a nearly sharp state and then the axe is heated once again and finally quenched in oil to harden. After hardening the axe went in to temper for an hour to remove stress and thus add resilience by reducing the brittleness of the edge.