Knifemaking Processes

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Custom, hand made knives for hunters and collectors   

Custom handmade knives and high performance cutlery for hunters, collectors, and chefs

Michael H Mara   sales@radharcknives.com  

(708) 969-2424   

 

 

On this page, I describe some of the processes I use to create the knives. These are intended for informational purposes only, and not as tutorials. Any process that a person reading this performs on their own is strictly at their own risk and responsibility. I shall not be held responsible for any damage or injury resulting from anyone attempting to duplicate these processes themselves.

Hand Forged Damascus Blades

These three photos show a Damascus blade in progress. On the left is the three smaller billets, the middle is them welded, and on the right, the finished blade.

Damascus or Pattern Welded steel is an ancient process that traces it's roots to India, thousands of years ago. The process as practiced today involves taking different steels, and even pure nickel, and combining them together via a process called forge welding. This is done by mating the metals carefully, bringing them up to forging heat, using some anhydrous borax as flux, and tapping them lightly with a hammer to set the welds. Once the welds are solid, the monolithic piece of metal may be worked as desired. I fold, twist, and continue to forge weld, in order to create the patterns that I achieve in the finished blades.

I enjoy working with various materials, including steel cable and chainsaw chain, in order to make some unusual and interesting patterns. Since I do this by hand, it is very time consuming and I don't make a lot of hand forged Damascus blades. It also adds to the cost of the finished knives.

 

Hand forged Damascus blade in progress

Hand forged Damascus blade out of chainsaw chain

Damascus blade forged out of chainsaw chain
Chainsaw Chain Damascus. On the top left is the initial billet, composed of two chainsaw chains. Bottom left is the sections of chain welded into a block, in preparation for the forge welding. The photo on the right is the finished blade, completely hand forged out of the two chainsaw chains.

 

Creating a Visible Temper Line (Hamon)

This is an ancient technique, perfected by the Japanese during the height of the Samurai era, for creating a differentially tempered blade. In making a blade, you strive, during heat treating, to reach a balance between hardness and toughness. The harder a blade is, the keener edge it will take and hold. However, too hard and it will snap, or at the very least, the edge will chip. Toughness is the opposite of hardness, hence why a blade is tempered after achieving maximum hardness, to make it more durable and not as prone to breakage. It's not as critical in knives, due to the shorter length, but in swords it was everything. The Japanese did this differential tempering via packing refractory (heat resistant) clay onto the spine of the blade, thereby preventing it from heating up as much as the edge, and also slowing it's cooling in the quench. This is a careful, time-consuming process, and works much better on simpler (less alloyed) steels than it does on the newer, fancier cutlery steels. I do this from time to time, in order to create the highest performing blade I can. If you do it correctly, you end up with a blade that's rock hard at the edge and dead soft at the spine. The different grain structures created in this way will show a visible temper line, or hamon.

Here is an upswept skinner blade, made of 1095, finish ground and hardened, showing the clay on the spine. It was hardened in oil, hence the black coating on the blade:

Another pic, showing the entire blade:

Off with the clay and clean it up. The pattern you see is surface decarburization. This is a loss of carbon at the surface that happens when the oxygen in the air combines with the steel during the heating. Although it's pretty, it needs to be ground off to get to the pure steel inside:

Decarb ground off, with the blade etched to show the hamon:

 

Decarb ground off, with the blade etched to show the hamon, another pic:

The finished knife:

Rear view. It worked well, the knife has a super hard edge and soft spine, and I was able to get a nice hamon:

 

A forging video:

Me Forge Welding some chainsaw chain

 Click on the photo above to see a short video of me forge welding some chainsaw chain

 

Wood Selection and Stabilization

I've spent a lot of time sourcing the finest possible selection of high quality exotic hardwoods from around the world and have over 60 varieties in stock. I strive to only use suppliers that sell sustainably harvested wood from non-endangered species. Curing some of these woods is quite challenging. Snakewood, for one, is one of the most difficult woods to cure correctly, to prevent it's natural tendency to check (small cracks appearing). When a green log is cut, to prevent any further curing you can coat the piece entirely with paraffin wax, especially the ends. The end grain is where most of the moisture escapes from as wood is curing. If you want to achieve gentle, controlled curing, you coat the piece of fresh cut wood with shellac, which is porous and will allow slow curing. Some woods are extremely stable (Bubinga, for example), and may simply be cut and set aside to age. Most all of the woods I have in stock, I have had here in my shop for anywhere from 6 months to 2+ years, so they have all been aged to ambient moisture content, and are ready to use.

Some woods are fully stable as is, and some benefit from a process called stabilization. I've sourced a proprietary chemical called Nelsonite, which was developed specifically for the process of stabilizing wood. Pool cue manufacturers use it, as does Scagel and other well known knifemakers. The chemical is carried in a Xylene solvent and the wood block, once cut, is then soaked in the Nelsonite for several days. The chemical makes it way into the wood, displacing the natural moisture and saturating the fibers. After soaking, the wood is air dried for several days to several weeks, allowing the Xylene to evaporate, leaving the Nelsonite inside the wood cells. What this does when the wood is used on a knife is to greatly prevent the wood from either absorbing or releasing moisture as it normally would, making it much more stable. Some woods do not need stabilization and indeed will suffer from it. Ask me about stabilizing woods, I can do that for you, should the wood need it, for a nominal extra charge. One of the major benefits of this method of stabilization is that the wood is left natural feeling, and will accept oil and wax finishes readily, whereas some of the more common methods rely on injected polymers, and leave the wood with a plastic like feeling and finish.  

Michael H Mara   sales@radharcknives.com   (708) 969-2424    

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