Why call it Trackside Forge?
I have two great passions in life apart from knifemaking – music and motorsport. So trackside, because of the many hours spent at race tracks but also as a nod to recording tracks or a music track. Oh, that and the abandoned railway that runs beside the forge. I couldn’t really call it anything else now, could I?
Anatomy of a knife.
There are really only two parts to a knife, the blade and the handle, you can tell which is which because one should hopefully be sharper than the other. However, there are almost infinite possibilities when it comes to the aesthetic design and functionality of each knife. So here are a few key things to know about hand forged knives and why they are superior in every way to mass produced, stamped blades.
Hand forging.
Forging is the most crucial part of the knife making process. Yes, it’s just a tremendous amount of fun and quite spectacular to watch, but there’s much more to it than randomly thumping a bit of hot metal into a rough shape. Steel is a bit like wood in that it has a grain structure within it, it’s on a microscopic level, but it’s there. When we heat and beat the steel, we compress and draw out the grain structure in a certain way so as to build strength into the very core of the blade, we also compress the mass of the steel along the length of the blade in order to form the basis of the cutting edge. A good cutting edge needs the steel to be hard enough, so even when ground down to the thinnest possible profile it will retain a razor-sharp edge without folding over or chipping.
Mass produced knives, even the very expensive high-end blades are essentially stamped out of a sheet of metal, then ground down by a CNC machine to the final shape. They may be ‘hand finished’ but that doesn’t mean hand started. No matter how well finished or expensive a knife, it will not have the strength or durability of a properly forged blade. How many knives do you have that are missing a tip because of being dropped on the kitchen floor? I have several, and you can see the large crystal grain structure within the blade so its no mystery why it snapped. I also have a kitchen tile with a lump chipped out of it where I accidentally dropped one of my knives, point down on the floor. The knife was completely unscathed, like it had been placed gently down upon a feather pillow, the tile is currently awaiting a little filler as my wife kindly reminds me as often as she can.
Why high carbon steel?
High carbon steel is defined as a steel with a carbon content of between 0.6% – 1.0%. We use high carbon steel because the higher the carbon content, the harder we can make the steel when it is quenched. Another advantage of carbon steel over stainless steel for example, is that once the knife is finished and put into use, the surface steel reacts with the acids and chemicals in the food we are cutting, forming a unique patina which looks absolutely beautiful.
Heat treating and tempering.
In short, quenching is the process of heating the steel to a critical temperature of around 800 degrees Celsius, holding it at that temperature for a certain time, then cooling rapidly in oil in order to change the chemical composition of the metal from softer austenite to hard martensite. It’s at this point a knife is born, because without the quenching process to harden the blade, it is too soft to properly hold a cutting edge.
Once the blade has been heat treated (quenched) it becomes much, much harder than untreated steel, but there’s a trade off. The harder the steel, the more brittle it becomes, so we temper the blade by re-heating to around 200 – 230 Celsius for an hour, obviously, for different types of steel the hardening and tempering process will vary. During tempering, the composition of the martensite changes as carbon atoms move out of the spaces between the iron atoms to form iron carbide particles. This relieves the strain within the martensite, reducing the brittleness of the blade which gives back a certain amount of flexibility while keeping the hard cutting edge.
Things to look out for when choosing a knife.
When it comes to kitchen knives, there are just too many variations of shape, style, function, size, etc. to get into here, but I’m guessing, if you’re reading this, you already know all this, so I’ll keep it simple by pointing out a few key things to consider.
Usually, the thing people notice first about a knife is the overall shape and style of the piece. Japanese, Western, hybrid, etc. these are usually defined by the shape of the blade and the type of handle. Like I say, we all have our preferences.
Next key feature, handles. They are either full tang or hidden tang. Full Tang means the back of the knife, or tang runs the whole way to the bottom of the handle, usually with shaped wooden scales on each side to form the rest of the handle grip.
Hidden Tang means that the tang is embedded in a cavity cut into the shaped wooden handle then pinned into place. For kitchen knives, a full tang isn’t necessarily better than a hidden tang, it really comes down to personal choice and how brutal you are on your knives. For camp knives a full tang is essential, no two ways about it.
Blade Finish.
After the structure of the blade has been forged, hardened, tempered and profiled on the grinder, its time to start working on how the blade will be finished. At this stage, the blade could be sharpened and a handle put on it, and the knife is done, but it wont look very nice with all the blackening and decarborisiation caused by heat treat and temper. So we can finish the blade off in many ways, either by polishing the steel to a mirror finish, usually seen on western style knives, or part polishing so that the forging marks (texture and undulations on the surface of the steel left by hammering during forging) are left behind. This is usually seen in Japanese style blades. Again, how the blade is finished is down to personal choice, but given the choice, I prefer to leave some forging marks as it attests to the hand forged nature of the knife. In fact, some manufacturers stamp a pattern on to their blades in order to make them look hand forged even when they have been stamped out of a sheet. Cheaters!