Text: Sean Woods. Images: Sean Wood and Hylton Ruterford.
Source: This article is taken from the July 2011 issue of Popular Mechanics.
Forging your own knife blade isn’t as difficult as you might think – but it’s not for sissies. Associate editor Sean Woods signs up for a knifemaking course, gets hot and tired, and emerges a few days later with a ‘perfect’ blade. His satisfaction is almost palpable…
A mammoth tusk that Rutherford is saving for a handle once the “right knife” comes along.
There’s something quite magical about forging the perfect blade. Like people, handcrafted blades may appear similar at first glance, but in reality no two are alike in every respect. Their myriad shapes, styles and sizes invariably have a specific purpose, so it stands to reason that if you want a finely honed blade that matches your personality and interests, you should ideally make it yourself.
Highly unlikely, you might think. Wrong, actually. Hylton Rutherford has been fashioning exquisite knives from recovered metals at his Johannesburg forge (Rutherford Forge) and selling them at the Bryanston Organic Market for the past three years. He also runs knifemaking courses, patiently guiding novices through the entire process – from choosing an appropriate design, forging and completing blade to fabricating its handle, as well as overseeing the creation leather sheath from scratch.
All materials are provided as part of the deal (if you want something exotic, such as a warthog bone or antler handle, you’ll pay a bit extra), and you can choose virtually any design you like. Only double-edged blades are out of bounds, he says, because their complexity makes them extremely challenging for novices. To ensure that his rock-solid standards are never compromised, he won’t take on more two students at a time. This approach clearly pays dividends: never had a knife made by a student that doesn’t make me proud. In fact, I’d be prepared to sell any of them at the market as my own.”
What’s reassuring is that you can tackle Rutherford’s course with no metalworking experience whatsoever. On this point, I’d say I’m a perfect example: at school, I dumped metalwork as a subject as soon as possible, dismissing it as a tedious and grimy activity to be avoided.
How things change. Under Rutherford’s tutelage – a mix of hands-on instruction and barrage of kindly advice – I managed to create a knife that made me feel incredibly proud. When he picked up my completed masterpiece, gave it a careful appraisal and announced “I reckon I could sell this knife for at least three grand”, my glow of satisfaction raised the ambient temperature by several degrees.
These blades are made for working
When it comes to knifemaking, Rutherford has no interest in anything that can cause harm to humans, explaining: “If someone wanted me to make a self-defence weapon, I would simply refuse. My lives are practical cutting tools, not weapons.” However, he does admit to making traditional fighting pieces on occasion – mainly out of respect for the ancient craftsmen and a desire to emulate what they achieved. As he tells it: “Even though these are technically ‘weapons’, they are only ever used for decorative or collection purposes, and making them helps me by honing my skills as a bladesmith.”
Because he wants his knives to be used rather than just admired, Rutherford prefers a matt, satin finish to a high-gloss mirror polish. Unless a client specifically asks him not to do so, he intentionally leaves some of the forging texture on the blade. He explains: “I’ve found that if I give my blades a more rough-and-ready look, my clients are more inclined to use them for their intended purpose.”
Although Rutherford prefers to craft his blades in the traditional way rather than adopt the more popular stock removal process (whereby one simply grinds surgical stainless steel into its desired shape), he has no intention of “reinventing the wheel”. As a result, he’s constantly on the lookout for modern 5160 spring steel – the best type for quality forged blades. “It has a high enough carbon content so it can be hardened to give a good cutting edge. It also has a small amount of chromium, which gives it incredible strength and durability.”
Interestingly, his preferred sources for this steel are leaf springs from Toyota Land Cruisers, Land Rovers and trucks, invariably sourced from scrapyards. He also likes using large industrial ball bearings, steel cabling (to create Damascus steel-like patterns), metal files and even old motorbike chains. “Once the chain has been forged into a solid mass, it creates a unique pattern in which you can still see all the links and studs.”
Designing a bespoke blade
Okay, now for something about me. I’ve just bought myself a traditional-design, 5,5 m day sailer with the intention of spending much of my leisure time offshore, armed only with a fishing rod, a sixpack… and a really cool fishing knife.
On being informed of my plans, Rutherford immediately grabbed some paper and began sketching a design. His running commentary can be summarised as follows: “The blade has to be long and thin with a slight curve, so you can fillet a decent-sized fish in one stroke.”
He decided that, because my knife would be exposed to water, it needed a white-tailed deer antler tine (or tip) for its handle. His rationale: North American antlers are much denser than their African counterparts because of the colder climate, and hence are more resistant to water. “I suggest we go for antler because of the aesthetics… it complements the blade beautifully. After all, looks are also important.”
Wild olive was chosen for the handle’s spacer because it’s a dense, relatively stable and oily wood that’s also resistant to water (“The beautiful grain is just a bonus”), while the bolster – the component that creates a waterproof barrier between the blade and handle – would be fabricated from stainless steel.
Knifemaking 101
That sorted, Rutherford fires up his gas-fuelled forge. I don welding gloves and safety glasses, and we get down to business. First, the billet (blank strip of spring steel) is popped into the furnace and brought up to a temperature of about 800 degrees.
‘Sometimes, a student might leave with a blade shaped slightly differently from the original design. But forging is only a part of the process. If the blade is stuffed up, we can always start again.’
To be honest, I have no idea what I’m doing, but Rutherford is ready to explain everything in the kind of language any novice can absorb: “Wait until the metal turns orange. If it’s yellow, it’s too hot, and if it’s red, it’s too cold.” This steady stream of good-humoured guidance continues throughout the knifemaking process, leaving me with very little opportunity to screw it up.
Once the glowing billet is in place on the anvil, I stand with my legs wide apart (the idea, he explains, is to maintain a stable base), hold the cold end of the metal bar firmly against my left hip (to keep it steady) and begin beating the daylights out of its tip to create a 45-degree angle that will eventually become the knife point.
Next job is to forge the choils (indentations on both sides of the blade where its cutting edge begins). Shaping the blade is accomplished by hammering the bevels (flat sides of the blade) on both sides down towards the tip to create the cutting edge, bevel and spine (back of the blade) thickness. Says Rutherford: “Forging metal is a bit like working with putty; you have to be able to envisage how and where the metal’s going to move.”
While you’re at it, you also hammer the spine towards the tip to make sure you have a good distal (taper) – a feature unique to forged blades. “It makes the knife light and quick, as well as extremely well balanced,” adds Rutherford.
It’s hard work. Being slightly built, and unused to wielding a heavy hammer, I find anything more than five accurate strikes, not to mention the distraction of preventing the billet from wobbling around while I’m hitting it, nigh on impossible. Once Rutherford’s teasing subsides (he’s seen this many times before), he advises me to “rather hit fast and accurate than heavy and slow, because you can’t put metal back once you’ve moved it. If it becomes too thin, you’re done.” Point taken.
Now that the hardest (or should that be most stressful?) part of the process is over, it’s time to forge the tang – the section of steel inside the knife’s handle. This is achieved by walloping two large dimples into the metal with Rutherford’s homemade tang tool, then – after estimating how much material is required – cutting the blade from the billet with a tool that resembles an axe. Rutherford elaborates: “Once the tang has been forged, it should have a length of about 10 cm and be tapered on its front and side profiles.”
The blade is then returned to the forge, brought up to red-hot and tapped gently to refine the metal’s grain structure along its cutting edge, and to ensure everything’s neat and straight. Now it’s time to “normalise” the blade.
My tutor explains: “Because we’ve placed the grain structure of the steel under stress by pounding it into another shape, we need to relieve the tension inside caused by the forging process.” This is achieved by heating it up to “critical” temperature three times, then allowing it to cool. When the blade is non-magnetic, says Rutherford (this is determined by lightly tapping it against a welding magnet), you’ve got it right.
That accomplished, the forge is swopped for a belt grinder. Using coarse grit, the blade is ground to its required shape, the forging scale is removed and the edge thickness is reduced to about 2 mm. Anything thinner would be a mistake, cautions Rutherford: “We don’t want to make it any thinner or it could crack while undergoing heat treatment.” Once I’ve achieved a nice edge geometry, all I need do is neaten up the tang. ‘
Because my blade has been “worked”, the steel is too soft to be of any practical use, so it needs to be differentially hardened to create a durable, springy spine and a hard, serviceable cutting edge. I apply kiln cement to the blade (to prevent heat from affecting it), leaving the cutting edge bare (so it can harden) and pop it back into the forge to bring it up to critical temperature. At this point, it’s quickly quenched in oil.
Now the blade is hard enough, but extremely brittle. As Rutherford explains, I need to reduce the brittleness without compromising the hardness, so the blade will have to be tempered. Rutherford achieves this by “cooking” it in his kitchen stove, to the chagrin of his entire family. As soon as he places my handiwork in the oven, wails begin emanating from the lounge “Oh no, Dad’s cooking blades again! It stinks! When are we going to eat supper?”
“Wait until the metal turns orange. If it’s yellow, it’s too hot, and if it’s red, it’s too cold.”
To temper a blade, it needs to be baked three times at 180 degrees for an hour, and quenched in water between each cycle. It’s then placed in the deep freeze overnight for sub-zero treatment. “We do this to refine the grain structure of the steel,” explains Rutherford. “If you broke the blade in half, you’d want to see a very fine silky grain towards the cutting edge and a coarser, large grain towards the spine.”
‘Sometimes, a student might leave with a blade shaped slightly differently from the original design. But forging is only a part of the process. If the blade is stuffed up, we can always start again.’With the heavy work out of the way on day one, day two is much more relaxed. My first task is to sand the blade by hand to remove the abrasive marks left by the grinder, a task that takes about an hour for each side. Starting with 200-grit water paper, I progress through the grades until finishing off with 1 200 grit.
Next, the blade is soaked in ferric chloride for about 10 minutes to bring out the “hamon” (a wavy line delineating the hard cutting edge from the softer spine). What can I say… it came out beautifully! In fact, Rutherford was quite envious: “The best temper lines I’ve ever had have always been with my students’ knives – it makes me quite jealous. It’s probably because with students, I tend to pay more attention to the process.”
All that remains for me to do is fabricate and assemble the handle, and make the knife’s leather sheath. Oh, and down a few well-deserved beers.
Rutherford is proud of the fact that he’s never had a failure on his course: “Sometimes, a student might leave with a blade shaped slightly differently from the original design. But forging is only a part of the process. If the blade is stuffed up, we can always start again.”
Rutherford’s knifemaking course runs for about two and a half days. Not only do you walk away with exactly what you want, but you get the same lifetime guarantee that he provides with all his blades.
Contact him on 082 654 9401 or visit his Web site at www.rutherford-forge.co.za
