Thursday, 16 August 2012

The Keeble Hoard: Swords, continued.

Two days ago I began welding and folding the steel to create the desired number of layers.  Today the sword is fully forged out with a tang forge welded on and I have begun the polishing.

Here’s the life story of this sword so far.

This sword was born from this 10 layer billet.
The initial welding pass. After this the billet was drawn out,

All the surfaces were ground clean

The billet was slashed to allow the folding (quadrupling the layers to forty)

This was welded together, drawn out again

and chopped into four (120 layers) and welded again. Shown next to partner billet.

This was folded a further three times and forged out to a billet around 16” long 2” with and half an inch thick. I did a very quick polish and etch to see what the steel was looking like. This was around a two minute etching in ferric chloride.

I decided that the steel did not require any further folding and so I moved on to the next stage of the swords manufacture which is to forge weld the two halves of folded steel around a soft core of iron or in this case mild steel. This is a medieval method of sword construction that has several benefits to consider.

 Firstly this method requires less “good” steel, which in historical terms meant a lower cost of raw materials as high quality carbon steel was a hugely expensive. Furthermore, folded steel (such as I have produced) can be used more sparingly, making it go further.

 Another benefit of this style is the incorporate a rod of un-hardenable material right through the heart of blade making it considerably less likely to break in use as and crack will quickly terminate when it runs into the soft core. This is the same principle as the Japanese tradition of kawahagane (hard jacket) and hagane (soft iron core).

So, the billet of folded steel was cut in half and polished on the internal face to allow a cleaner initial weld and a rod of 16mm low carbon steel was MIG welded into the centre of each side. It would be possible to do without the arc welding, with careful use of tongs, but it just makes life simpler to know that the three components are secure to start with.

When at temperature, the steel envelopes the core and then welds to itself seamlessly. This took several passes under Goliath  as I wanted it to all be done at the hottest possible temperature. Lots of flux was used and the steel was allowed to sit at the high temp for several minutes each time to ensure the borax could really get to work on all surfaces dissolving any scale.

The gap closes up and we can begin drawing out the steel to the desired length as well as setting in the distal taper.

Once the rough length has been achieved I switch to using just hand hammers.

and thats all i can show you tonight. thanks for looking. more tommorow.

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