It’s a Marcus thing

People were wondering why I put a picture of a Fight Club bar of soap on my post about Marcus Ranum. It’s because he’s a maker — he makes things like bars of soap. I should have just used my own bar of Marcus Ranum soap, but as you’ll see below, it’s been in my office gathering cat hair.

I also have one of his knives.

If ever I have to fight off a crazed attacker, that would be my weapon of choice. It’s wicked sharp and pointy. And then I could wash the blood off with a bar of soap.

Everyone, keep an eye on Marcus, he’s home alone.


  1. wzrd1 says

    Two of my favorite things, a good bar of brown soap (seriously!) and a quality knife that holds an edge.
    There are two kinds of knives for me, the one I don’t give a damn about and once broken or badly deformed, it’s trash and the one you’ll always see me reach for when I need a knife. I only have a few of the latter, but I’m always in the market for specific task knives, such as a really good boning knife and a really good skinning knife (had one, but it got lost in a move).
    Although, that blade looks excellent for fishing, were I ever to get into fishing. Personally though, I’m more of a make a fish trap, pick what I want from the trap and release the lot after feeding them for their inconvenience. Gotta prepare for tomorrow and all!
    Speaking of which, not getting to the supermarket soon, so anyone that can spare some catfish, cod or sole, kindly attach some to an e-mail and shoot it along. ;)

  2. PaulBC says


    Two of my favorite things, a good bar of brown soap (seriously!) and a quality knife that holds an edge.

    As they say, “the only two things in life that make it worth living.” No wait, those are different. I’m not a huge fan of “outlaw” country or anything, but if that question is ever on the exam, I know the answer.

    When I first saw the picture, I thought it was a rubber stamp carved out of a gum eraser. Maybe Marcus does that too. (It should have tipped me off that the writing isn’t reversed.)

  3. birgerjohansson says

    If you need ti fight off climate wreckers in big urban SUVs, you can do what people in Edinburgh did, and insert stuff in the ventiles that make the decks deflate. No permanent damage, but in USA it would probably be called terrorism.

  4. birgerjohansson says

    In one of the William Gibson novels, the protagonist confiscated a nasty ceramic knife with a “fractal” edge from a thief that tried to stab him when he worked as a rentacop. Are such abominations already here, or are they awaiting us in a future when anything can be 3D-printed?

  5. lochaber says


    I couldn’t remember that specifically, so I had to go looking for it, and here’s what I found:

    Sounds like it was the bike-courier who had it.

    There are currently ceramic knives, but I believe most of them are not serrated, and I’m under the impression that they are probably a little to brittle, and the serrations would be liable to break off. As is, the current ceramic knives are prone to chipping, but do hold an edge pretty well, and are pretty much immune to corrosion…

    As to the “fractal” edge, I’m under the impression that it basically was serrated, and the serrations had serrations of their own, etc. I imagine that a knifemaker could make that, but it would be time-consuming and expensive, probably difficult to automate, and would make sharpening difficult…

    I don’t know if they could be 3-D printed, but I think it would be difficult, and possibly unnecessary.

  6. PaulBC says

    @4 @6

    3D printing strikes me as a very uninteresting way to get a fractal knife edge. If I were fantasizing about some futuristic approach, it would result from the self-organization of nanoconstructors producing something along the lines of romanesco broccoli but confined to the plane. Or possibly, the serrations could extend into three dimensions once they were smaller than the desired thickness of the blade.

    Switching back to present technology and more practical considerations, I don’t understand the purpose. I think that a periodic row of non-fractal teeth probably has the same cutting power as a fractal.

  7. says

    Ceramic knives exist. They chip really easily; do not recommend. Although Boker made a really pretty ceramic folder in a titanium frame. Someone gave me one of those in 1989 and I still have it.

    What would an insane “spare no expense” knife look like? And let’s throw in some fractals. The blade is curved like a katana, but let’s say it’s shorter – we are aiming for something that is basically an osoraku. I like them a lot, ok? And the fractals: the edge is serrated with serrations that are recursively lensed. This would be an absolutely heinous cutting edge because the serrations would encounter the target at different depths, thus for all intents and purposes having single-point cutting. I can’t draw it but imagine stacked shark’s teeth only thinner. Thinner and carbide. Carbide digitally printed into a supporting matrix of carbon/carbon: the stuff space shuttle wings are made of. Carbon/carbon is feather light, incredibly strong, and it can handle re-entry temperatures. So you can use it to cut your steaks while they are still in the grill, and the grill is fired with liquid oxygen and aluminum. Your steak will taste like shit but everyone will see it from orbit. This knife would be tough enough that you could just poke that ole steak onto the tip and – oops – it’s dust. The carbon/carbon and tungsten would be unaffected. You would need a welding hood and some kind of gloves.

    Let me try to describe the edge a bit better. Imagine a lenticular blade, let’s start with about the size of a dime for the main plane, about 1mm thick. That 1mm tapers to an invisible, nearly nonexistent edge at the cutting edge. Then there are smaller versions of the cutter, recursively getting smaller, but you can stack them inside the carbon/carbon as you’re printing it. It’s really what you’d get if you mixed a shark with a bandsaw.

    Prototype cost: $400,000. I know for a fact that a piece of space shuttle leading edge cost $250,000. I have held one. They are not scary. This knife would cut a tuna in half with one stroke. This knife, unlike space shuttle wing, is scary. Unlike a katana, it would not leave a pretty cut. That’s why I will stick to katanas if I ever make more killing blades.

    You could saw with it, too. Mild steel would shred like gruyêre. Tool steel is tool steel, leave that stuff alone. But here is the fun part: you take a piece of S7 tool steel and shape it into a scary bad-ass combat knife like Rambo’s. Then, you put The Fractal Hellblade next to it. And you fire up your oxy/acetylene torch and chop the S7 knife apart. An oxy torch would cut the S7 like cheese. When you shut the torch gas down, the Fractal Hellblade is sitting in a puddle of S7, completely unaffected.

    If you really wanted to fuck something up you could attach it to the leading edge of a space shuttle wing and fly that into something.

    Thanks for the fun exercise. I have followed that train of thought before and usually come down to a plain edge-geometry carbon/carbon katana with a carbide edge. It wouldn’t have super powers, but it’d mark anything but diamond (which is carbon too!) (carbon crystal grudge match!) I just prefer the katana blade geometry for aesthetic reasons. But I think that merely the sight of a Fractal Hellblade would cause uncontrolled urination. A person encountering a carbon/carbon/carbide katana would reasonably stand, immersed in its beauty. Since carbon/carbon is light, let’s 3d print us an ō-dachi. You know: Sephiroth’s sword. Let’s say that would be an evil weapon but there is no moral value to steel. Because of the kind of cut the Fractal Hellblade would leave, it would be a vile weapon.

  8. says

    I think that a periodic row of non-fractal teeth probably has the same cutting power as a fractal.

    Yeah. It’s the single-point cutting that’s the thing. Its why bandsaws cut so well.

  9. says

    PZ that soap bar looks horrible. I can bang out a few in resin if anybody wants one. It ought to be within my capabilities and I have time.

  10. says

    birgerjohansson @ #3

    … insert stuff in the ventiles that make the decks deflate.

    I’m sure this makes perfect sense if one knows what “ventiles” and “decks” refer to.