New Axe Design Employs 2 Simple Machines; Chops Wood Splitting Effort in Half

If you’re from a frigid woodland state like I am, chopping wood was a permanent fixture on the list of household chores growing up. And unfortunately for us Northerners, as technologically advanced as society has become, there still remains no more practical way to make kindling than swinging an axe. But thanks to a simple twist of physics, this backbreaking task may have just gotten a bit easier.

A Finnish inventor with a name every bit as cool as you’d hope, Heikki Karna, has invented a revolutionary new axe called the “Vipukirves,” a Finnish word which translates to lever axe. In addition to capturing the mechanical advantage of the wedge, it also manages to utilize the effect of a lever.

Regular axes just use the wedge effect and need to be driven downward with enough force that the axe head can split a log along its grain. For anybody who isn’t Paul Bunyan, this usually requires a few swings (and maybe 3 embarrassing whiffs) to actually get the log to split. But the lever effect means that a single swing of the axe can create a split in the wood that is 8 cm wide – a distance that will usually mean the log is now two logs.

Here’s how it works: As you can see, the axe head is actually set off to one side. This means that when the blade enters the wood (purely on the force you give it) the axe head naturally rolls over to one side and immediately starts acting as a lever to push the pieces apart from one another.

Axe IP

The basic physics behind the Vipkirves. (

This design is especially good news for those axe swingers who don’t appreciate the sudden shock of impact on their supple wrists. Because the Vipukirves rotates immediately after impact, some of the energy is dissipated through the axe head instead of being sent back to the handler.

Tell us what you think, nerds of the Northlands – is the mechanical advantage of the Vipukirves worth the $215 price tag, or are you willing to stick to one simple machine when it comes to wood splitting?


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  • I’ve cut A LOT of wood and it seems like it would be neat to try out but do I think it’s worth $215? Nope. Sure it takes a less forceful swing but the rest of your body will tense up and you try to chop faster resulting in the odd body movement you see in the video. Frantic chopping leads to accidents. I’m glad I have gas heat now.

  • It’s a super simple application of physics to a longstanding high-labor task. Very cool and totally up the alley of the Nerdist flock. And while it might be expensive now, that’s to be expected for any next-step technology right when it’s introduced.

  • It’s on nerdist cause its sciencey and all things sciencey are therefor nerdy. Being a nerd is way more about getting excited over new axe designed using simple machines then it is about geek culture.

  • So the handle will twist in your hands every time you make contact with the wood. Looks like a surefire way to get a wrist injury.
    Seems to me that having the handle, center of gravity, and blade all lined up would also improve accuracy aside from helping to avoid injury. I will be avoiding this product.

  • If you notice in the video, they demonstrations they do use preselected logs with VERY straight-grain and are dry/frozen. Hell, using a normal ax, it doesn’t take too much force to split one of those types of logs. I want to see how it does with a log that has a knot in the middle of it or just a log that isn’t an “ideal” cut.

  • In the video you see the ax turn a complete 90 degrees on impact several times. That is an accident/injury just waiting to happen. He is making pretty quick work of clear straight grained logs. Id like to see how it does on a gnarly piece of applewood or something similar. I can cut up straight oak about as fast with a standard axe. For the price tag you can buy a decent used power splitter. Now the tire on the chopping block I like that idea and will give it a try.

  • this is awesome, way to improve on the wheel guy. weird to find it on Nerdist but i guess it’s a tech-gadget? and definitely necessary apocalypse gear!!

  • Good Lord; enough with the zombies. The concept is great, but I would certainly be skeptical about a wrist injury. The wood in the demonstration is unlike the wood that most of us in the southern swamps will have at our disposal. Has anyone split ash, oak, pecan, willow, or sycamore with this thing? I also like the tire set up. Simple, but brilliant. Baker Vinci

  • As a longtime wood cutter I would have to agree that that wood looked ideal. Never needed help with that kind of stuff. If there were a knot in the wood I would think the shape would prevent one from chopping further down into the wood to break a difficult area.

    Demo this axe on knotty pine.

    They mention the impact not being transferred into the handle but I would think the sudden twisting action would be painful or harmful on the wrists.

    They make mechanical wood splitters for as low as $500 which takes most of the work out of it. Seems pricey for an axe you still have to swing.

  • $215 buys a lot of gas for my log splitter. I too see wrist injuries happening with that axe. Let’s see him do that with a Elm log that spent its whole in the wind. Now the tire is a good idea. K.I.S.S. When I fell a tree there is always a bunch of dead branches of varrying sizes if I need kindling.

  • No redneck American is going to be impressed by something that relieves them of the right to look tough swinging an axe, bare chested down on the farm. Especially when it has been invented by a European.

  • The bigger advancement to me is splitting the wood in a tire. That sounds like VERY dry wood, and it’s extremely straight-grained. Nearly any axe could do that with wood like that. Show me what it does with beech, birch or oak…in other words, what LBJ said when I was beaten to it…

  • Oops, spoke too soon. There is some birch in there towards the end. My bad. Still seemed to be much straighter-grained than what I’m usually dealing with…maybe the axe is so good that it makes the job look easy? 

  • I would like to see them split a twisty gnarled old piece of blackjack oak, or hickory, or something really hard like what grows around here, I dont think it would split so nicely.  There are some oaks Ive put under my log splitter that IT couldnt hardly handle.  Im terribly skeptical…

  • Several questions.

    How long would it have taken to split that wood with another ax? It seams like the wood was very dry and ready to split.

    When will this be available at a more reasonable price? Special design aside, it is a forged head with heat treatment. just like every other ax on the market, and will be quite simple to mass produce and the current price is well above the law of diminishing returns.

  • Hello.

    My name is Heikki Kärnä. I am the inventor of the Vipukirves/Leveraxe.

    I red the comments and I noticed, that for some people it seems to be very difficult to understand the splitting technique with the Vipukirves/Leveraxe.

    There is practically nothing to do with cutting and wedging when splitting with the Vipukirves.

    Leverage is the way how to do it.

    There is no friction as with the conventional axes and mauls, because on an optimum strike the blade penetrates into the block only about 5 millimetres, less than a quarter of an inch. At the very moment, when the edge of the blade touches the surface of the block, the blade starts to lean to the right. Here comes the leverage that multiplies the splitting force up to 35 times bigger. The edge of the blade grabs to the side of the part of wood. All the kinetic energy turns to the left and pushes the piece away. Initial spitting force can be even 15 tons.

    Splitting is now much easier, because you do not have to use so much power. By holding the handle as gently as possible you allow the rotation in your hands. You will not get such chocks to your hands and body as with the conventional axes and mauls.

    It is very important to hold the handle so, that you do not resist the rotation.

    This way also the safety elements, which are build in to the design of the blade, function as they are planned to do. The blade will stop on the top of the block, or slows down the speed so, that it is fully under the control of the user.

    Vipukirves has been on the market over 8 years. There has happened NO ACCIDENT.

    It is advisable to split the wood as green as possible, because this way it splits easiest, the insects cannot multiply in it and it dries best.

    Vipukirves has spread all around the world. The feed back is excellent.

    There is a lot information in my websites, Google etc. Youtube. Search by words Vipukirves and Leveraxe.

    I wish you to make yourselves acquainted with this new kind of tool which is in commercial production first time in the history. I would also like you to understand that among the other advantages the safety elements make the splitting really enjoyable because you do not have to be afraid all the time about the blade.

    Based to the feed back, so called hard wood is not any more a problem when using the Vipukirves.

    Of course it requires some knowledge about the structure of the tree to optimize the splitting.

    In the videos you can see myself splitting. I am around 70 years. Now I am 74 and my total experience in splitting firewood consists of 67 years time.

    Read more:

  • It looks to be a very good product, and the aspect of the axe has been evolution, the price is a little high it needs to be lowered greatly for it to meet the public demands. 

  • Wood to small to burn in wood stove. It will burn up to fast.  Log that size would make four nice pieces to burn in stove or fire place. 
    The pieces he was splitting would be nice to burn in a fire place to watch with girl friend.
    I split a log that size into four to six pieces.  I would put six pieces in my wood stove and it would burn all night.  Log needs to be a little longer also. Would cut my logs by using chainsaw as ruler. Cut the length of motor and bar together.  Around 26″. I built my stove around 30″ deep. I’ve built a lot of wood stove in my welding shop. Not all would be that deep. A little smaller for most to sale.
    Plus I built wood splitters also.  Works great with wood with knots. Not sure how that axe works with a tree full of knots. Think his arm will be tired after a log or two.  
    Thanks everyone for putting up with me. I’m gone fore now. JCRIII