Building A Knife By Hand Is Just As Hard As You Think

Carl Sagan once said: “If you wish to make an apple pie from scratch, you must first invent the universe.” In other words, the term “scratch” is really a relative sort of thing. Did you grow the apples? Did you plant the wheat to make the flour? Where do you keep your windmill, incidentally? With Carl’s words in mind, we suppose we can’t say that [Flannagill] truly built this incredible knife from scratch, after all, he ordered the sheet steel on Amazon. But we think it’s close enough.

He was kind enough to document the epic build in fantastic detail, including (crucially), the missteps he made along the way. While none of the mistakes were big enough to derail the project, he mentions a few instances where he wasted time and money trying to take shortcuts. Even if making your own knives at home isn’t on your short list of summer projects, we’d wager there’s something in this build log you can learn from regardless.

So how does one build a knife? Slowly and methodically, if what [Flannagill] has written up is any indication. It started with a sketch of the knife on a piece of paper, the outline of which was then transferred to a piece of tool steel with nothing more exotic than a permanent marker. An angle grinder was then used to follow the outline and create the rough shape of the final knife.

From there, the process is done almost entirely with hand files. Here [Flannagill] gives one of his most important pieces of advice: don’t cheap out on the tools. He bought the cheapest set of files he could, and paid the price: he says it took up to 14 hours to complete just one side of the knife. Once he switched over to higher quality files, the rest of the work went much faster.

After filing and sanding the knife blank, it went into a charcoal fire to be hardened, followed by a total of 4 hours in a 200 C (~400 F) oven to heat temper it. Finally the handle pieces (which are officially known as “scales”) were attached, and finished with considerably less labor intensive woodworking methods. The final result is a gorgeous one of a kind specimen that [Flannagill] is rightly very proud of.

If you’re worried this process looks a bit too quick and easy for you, don’t worry. You can always go the [Bil Herd] route and make a forge out of your old sink if you’d rather start your apple pie a bit closer to the tree.

47 thoughts on “Building A Knife By Hand Is Just As Hard As You Think

  1. Why sharp tip though? This kind of knives is serously hazardous and can be used for murder. It’s much better to buy ones that by design can’t be used for stabbing others.

    1. Have you ever considered not giving other people advice about things you obviously know nothing about? The type of knife pictures is called a camp knife and there are damned good reasons its shaped the way it is. And no, those reasons have nothing to do with killing people.

    2. While there ARE applications where a knife that can’t stab is desirable, you’re straight-up wrong to say that knives with sharp tips should never be purchased or made. Many cutting tasks require a sharp narrow point, so a blunt-tipped knife is missing important knife functionality.

      Regarding usefulness for murder: the best prevention for murder is NOT MURDERING. If someone wants to murder, they’re not going to be stopped by their knives lacking stabbing tips. Heck, as you can see, it’s entirely possible to MAKE a stabbing knife from raw materials; how much easier do you think it would be to just PUT a stabbing point on a knife, or anything metal? How long do you think it would take to sharpen a screwdriver’s tip?

      You don’t make a dog safe by pulling its teeth. You make a dog safe by loving it and socializing it so it doesn’t feel the need to bite.

      1. Whilst you might think obviuous troll, worryingly today there are too many people that actually think like this.
        Dont dismiss the victim mentality as merely pathetic, they are changing things for the worse.

  2. This is a well-documented build, and a very attractive end result.

    Having said that, I’m disappointed at the amount of hyperbole in the write-up. Slow and methodical, sure. “Epic” build, no. It’s a sheet of steel, tediously filed and glued to some scraps of fiberglass, which are then sanded. I realize that roughly half the Hackaday staff is intimidated by anything sturdier than solder unless they can get CNC to do the work for them, but if this is an epic build then some of the stuff you find on home machinist forums must be roughly on par with the creation of the universe.

    1. Sounds like you’re into some really hardcore stuff. I’m assuming you’ve already submitted some of your projects to Hackaday? Post the link so we can all see what a real man works on.

  3. “Carl Sagan once said: “If you wish to make an apple pie from scratch, you must first invent the universe.””

    Let there be light, so how well did I do?

  4. >>He bought the cheapest set of files he could

    It’s almost always more cost effective to buy the few files you actually need, quality is severely lacking in most assortments and you don’t need half the files they give you. Even cheap files can still be good. A big hazard fraught mill file then buy a decent pack of chainsaw files for detail work. Maybe an assortment of wet dry paper used on a sanding block or purpose build holder (clickspring has a video on emery sticks).
    If you’re steady handed you could do it all with a grinding disk or die grinder but you’ve gotta make sure you don’t burn the steel.

    1. I used to buy the cheap sets of tools, my logic was, if I break an item, I’ll replace it with one of quality.
      And so when a socket and it’s ratchet broke changing the rear wheel bearings of a VW Rabbit, that’s what I did!

        1. And then cheap tool bites you in the eye for example by screwing the screw because it’s tolerance is out of the window or like leaves hazardous residue on oil pan tissue. Sorry english is not my primary.

        2. I do the same and what I’ve found is that 15+years ago cheap tools were cheap tools but there were still good ones to be found.
          Now things have changed such that since every brand is making them in China anyway, price isn’t always a sign of quality. Sure the cheap crap tools have dropped even further, but 1000’s of sellers are selling the same stuff at different price levels for exactly the same thing. It’s a mind field now.

          I bought some cheap sockets 15 yerars ago. They are invincible. I’d love another set but the band is long gone.

    2. Its a learning curve, some cheap tools do the job, but usually where material properties matter most, cheap tools tend to fail. Files are a great example (been there). Another is jigsaws vs drills. The difference between cheap and expensive jigsaws is much larger than the difference between cheap and expensive drills. I own a number of cheap drills which work well, but I only use my good jigsaw, the cheap jigsaws should probably be turned into something, or given away. Rotational bearings are relatively easy and cheap to make well, in my experience, wherever any motion other than rotational is needed, spending a little more makes sense.

      One place I have found cheap tools to make good scene is in the rarely used brute force fields. I have a number of DIY task specific boxes. Like my plumbing box, it includes a few cheap spanners, a couple of large cheap shifting spanners some cheap gloves a cheap gas burner, solder etc. My grinding box includes its own set of gloves, glasses, earmuffs grinder etc. So tools are duplicated in multiple boxes, each per function, low use, low precision requirement, so cheap makes sense. My router box includes its own glasses, earmuffs, and a 17mm spanner for tightening the chuck. This way you don’t need to look for this tool or that, you only need to fetch a box by function, and it will include all you (90% of the time) need.

  5. In keeping with the Sagan quote, looks like he didn’t dig up and process the or?. Many hobby knife builders use car springs. The front axle leaf springs fro old cars and pickups are preferred, because they are flat except for the Ford traverse springs. Past co worker of mine when looking for inexpensive file he look for those made in India, because he found them of acceptable quality. That was in the ’70s

      1. I once made a punch for punching out nail holes in horseshoes from an old coil spring and a hammer knife for cutting clinched over nails from a leaf spring. They were the best tools I’ve ever owned for edge holding and taking abuse.

  6. I’ve started a knife project of my own this summer. I’m making a W49 Bowie. Started with a wheel horse mower blade. I’ve got the blank cut out. Need to start shaping the contours on the sides and then heat treat. After that, sharp edges and finish work.

  7. I know a couple of master knifesmiths, and I’m afraid the process here isn’t the one they use.

    Steel has a microcrystalline structure similar to the grain in wood. All forms of abrasion remove metal without changing the grain, and leave exposed shear planes at the surface where cracks can form. Smiths forge the shape, distorting the microstructure as the bulk metal changes shape, and keeping the shear planes more or less parallel to the surfaces. The process also introduces stress in a way that makes the blade stronger against external forces.

    Heating the metal lets the crystal lattice change its bonds and release some of the stress, so learning the effects of hot-forging and cold-forging, and when to use them in the shaping process, is a big part of the learning curve.

    One of the smiths I know demonstrates the difference by clamping a cut knife edge-up in on a block of wood, setting the edge of a forged knife across it, then driving the forged knife through with a 3-pound hammer. If the edge of the forged knife chips or dulls, or the back mushrooms, he considers that one a dud.

    1. Properly forged tools are generally better better but then you have to worry about keeping thermal regime of your steel – othervise it will decarbonize, or get screwed in some other obscure way. With subtractive process (file/grinder) it is not a problem, when blank gets too hot to keep in hand you just stop for a while. Process and equipment are simpler (and cheaper) than forging -because to finish forged knife you need grinder anyway. And ground (not forged) blades are doing just fine, from surgical scalpels to general purpose survival/combat knives to HSS lathe knives, drills and endmills. So there is a lot of knifemakers that do not use forging and results are sufficient because when was last time you had to cut other knife with your knife?

    2. Nobody ever said this is how knives are forged. It’s probaby safe to assume this guy doesn’t have a forge or anvil handy, so he’s working with materials and tools that the average person can get from the hardware store.

  8. Yeah it’s a hunting knife mostly used for cutting flesh and kindling, flesh for cooking that is. Keep it out of a workshop. Very prone to gross accidents. As the point is used many times over it dulls and it evolves into the classic drop point by repeated sharpening. They mostly started out straight for utility. The point is the point is rapidly dulled by cutting against hard surfaces like bone, pottery, and metal.

  9. Ok, writeup is damned hyperbole. Is this because its not electronics based?

    It is not hard to make a knife this way. There are 50$ knife kits sold like this to make your own knife just like this. Its actually pretty simple. Only heat treating takes more knowledge, but even thats really not that bad.

    Very simple- buy a bar of flat steel of hardenable grade from mcmaster carr. O-1 steel is great and not that bad pricewise. Mark shape with sharpie, cut out oun metal bandsaw and cool frequently with water. Or just use a bench grinder for a few hours, cool off a lot with a cup of water. Presharpen with grinder, belt sander, and a 5$ file from a good maker like nicholson. Grobet is best for files though. Heat treat in oil for O-1, rough away some scale- and temper to purple color. Finish sharpen with 20$ ez-hone diamond hand laps. You can get them on Amazon. Cut scales, glue on- drill holes thru handle and scales with handdrill. Pin with brass rod.

    Walla, a knife. Sounds harder than it actually is!

    I blacksmith for 3 years now, with 2 different groups- want to really make a knife? Smith one. That’s harder. Still, not that complex- I swear. Damascus is challenging. That’s all.

    1. A blacksmith elitist, seriously? Obviously since this project isn’t better than what you’ve done personally, nobody should be interested in it, right? You sound like a really bitter and sad person.

      Also don’t understand what you stand to prove by writing out the “simple” explanation for making a blade out of flat stock that was already well photographed and explained in OP’s project. Maybe you didn’t even bother to read it?

  10. My father made a sharp knife from saw blade and it is super sharp when I touched it with fingers. Now I dare not use it because I scare my children will play with it. As far as I know, you can make a knife from just a piece of steel with either grinding stones or belt sander. Hope that helps.

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