Geek-Fest, Practical Axe Wisdom Decoded, -LARGE- V.S. -small- MASS X VELOCITY = MOMENTUM
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- Опубликовано: 31 янв 2025
- Basic physics of how to use different sized axe heads, Mass, Velocity, Momentum, inertia and Physical efficiency in chopping wood. Read the accompanying blog post @ skillcult.com/b...
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It is often said let the axe do the work, or similar. In Elsworth Jaeger's Wildwood Wisdom, he says that it is the weight of the axe that does the work. That is not true, it is momentum, which is a combination of mass and velocity. The axe head must be moving to do work and the part we can change with any given axe is the speed at which the head is moving. The basic equation is Mass & Velocity = Momentum. The wood that is being chopped has inertia. It is still and does not want to move. The Axe has forward inertia. It is moving and it does not want to stop. When the two collide, you have the potential to do work. If the velocity of any given axe head is increased by swinging with more energy or better technique, the potential to do more work is created.
Understanding this concept can help you dial in your technique and know for sure that velocity is the main thing in the equation that you can change.
It is sometimes said that a heavy axe can do more work with less effort, because the weight will do the work. But, the heavy axe is more tiring to lift and swing. It does have more potential to do more work if it is swung hard, but not everyone is up to that task. If you decrease an axe weight by half and expend the same amount of energy using it, the amount of work done will not decrease by half, because velocity will be increased. There is a cost to increasing it's velocity, but that has to be weighed against the fact that a heavier axe has to be lifted over and over and that it is both harder to lift and requires more energy to swing at the same speed as a lighter axe.
Please forgive and overlook any minor errors in terminology and physics principals. I only care about the practical principals and I believe that those are accurate enough. If not feel free to correct me. There are of course more questions that are raised by this examination, such as even if two momentums are considered equivalent, how does a heavier mass react when striking wood v.s. a lighter one. There are many factors that go into effective chopping. This is only intended to really examine one aspect.
I agree with every point you have made. I think an important component of the heavy vs. light axe controversy is the extra energy expended to lift the axe after a swing. I know this is not the topic of this video but I think its an interesting thing to think about while geeking out over the physics of axes. This extra energy expended when using a heavy axe is lost. I think this is why a lighter axe is more efficient up to a point. You put in roughly the same energy to swing the heavy or light axe into the wood, The light axe just hits faster if done correctly. So the momentum is similar and work done is similar but you have to do more work after the swing to ready the heavy axe for another blow.
J Vanier I'm interested in what you consider light, and what would be heavy.
I think the weight-spectrum is also conditioned on technique. I don't swing a light axe the same way as a heavy one, using much more rounded body-weight/movement on the latter to avoid localized fatigue
if not too heavy, I get more done quicker, but I'll get more profoundly tired when done. In the short run, heavy good. In the long run, not so much if not accustomed (or if one likes to perceive oneself as The Hulk, only to have a hard fall from grace)
I think the author was speaking to the beginner axer. So he didn't get too technical.
I consider the boys axe to be light. 2.25Ibs to 3Ibs. Heavy is 3.5 or 4 for me. I don't prefer over 3.5 it seams.
I know this is an older video, but the units of work and kinetic energy are equivalent (I’m talking about classical, non-relativistic physics). The kinetic energy is ½ mass times velocity squared. In other words, KE varies as the square of the velocity (and only directly as mass). Twice as fast means four times the energy, whereas twice the mass means twice the energy. Hope that makes sense.
Great basic primer, for any newbie. Loaded with knowledge and practical experience.
Having plenty of lifetime experience, I must be an axe nerd to have sat quietly through this whole dissertation! :) Good stuff, Steven...Thanks!
I'm glad you learned something about yourself :)
Irma took down a red oak in my neighbors yard so I've been chopping happily. I read a comment about mass of different wood types. This is dense wood to buck. I started with my 3.5# db with the 36 inch handle for the larger trunk. Then I began to compare a heavier bit with a 30 inch handle. The 4# did much better removing the dense wood. I feel like I swung the 4 with the same velocity and accuracy as the 3.5. Maybe the two different handle lengths played a role in the amount of work done, I not sure. Maybe it all evened out. Anywho, I'm enjoying this discussion and hurting my brain in the process.
Keep em coming.
Cool. I need to get some heavy axes on short handles to play with. Still planning to move up and do real comparisons over years. I've been curious to watch you because you use a lot of different sizes and lengths. Look forward to what you find out.
Hillbilly physics - my favourite.
Just found your channel and loving the content, especially the axe stuff.
I've self-taught myself much of what I've learned but learned equally as much from your videos in a short time.
Best wishes from England (The North)
Welcome, glad to have you around.
This is fascinating. Since I'm all of 115 lbs, an axe is a lot of energy for me. when I chopped over my head and downward, I would give it a pull as it passed overhead then allowed the weight and momentum to take over. I agree on the momentum, it's a feel, a groove. I have yet to be able to chop horizontally. It's all about the conserving energy and what works for one person, won't for another. As you said here. I thought I was the only one who thought about stuff like this. Oh, that point where you have to break it's inertia to get it moving is the "moment" of inertia.
I tend to go nerd level 10 on this kind of stuff :). I'm very unfamiliar with the math and science and tend to avoid it, or much in the way of trying to actually calculate anything, because I don't think it's that relevant considering individual skills, workstyle, size, conditioning etc. The important bit I want to get across is just the concept that with any given axe, velocity is the variable to work on regarding the momentum of the tool. it's kind of a game changer for people in terms of dialing in better technique and efficiency. One discussion that rarely happens around this stuff is energy expenditure to work done. Many have pointed out here that in the m x v = momentum equation, more speed is more effective than more mass, but approximately never is the energy expenditure considered when assessing the relevance of that fact. Energy efficiency is kind of the interesting bit. It is largely invisible and certainly incalculable. One person can expend enormous amounts of energy and get very little done and another can expend much less and get a lot done. there is obviously technique and strategy, but there is also a lot of invisible tension, unnecessary movement or lack of, etc.
SkillCult So cool. I nerd out over efficiency. It’s pretty much my life obsession. It affects everything. Former athlete and energy conservation was everything. As a drummer it’s the same. Any activity that can run you down but you need to sustain power AND accuracy energy MUST be part of the equation. Especially when the energy you are burning is your food. Or if you are working against daylight or storms or heat. There’s also conserving emotional energy, limiting stress energy. All of life is measured in energy expenditure. 🤓
I studied the math and science only because I love it but it’s only a stepping stone for higher level science where practical experiments would be impossible. It’s theoretical and really has no bearing on real life other then giving you a few words to explain a concept. What you do in this video is perfect, a little simple math but real experience with well examined possibilities. I love the comments section and the discussions too.
@@AmanitaDreamer Agreed all around. It's a hard thing to teach. As hard as the actual physical part is just that it matters. Some might say "get a life" to someone who thinks about tweaking daily tasks to be more time or energy efficient, but that is literally how to get more of a life! I'm not all in on energy efficiency all the time. I like to play and do go hard sometimes, but no doubt many could use a lot more attention to it.
SkillCult LOL That’s what play is ... going hard without having to think too much on it!! Having a good time with your channel!
The only time weight does any of the work is when you're swinging vertically, because it adds to your momentum. But swinging horizontally, the weight, if anything subtracts from your aim, if it makes a difference at all, practically.
Love these vids! Thank you for taking the time to make them! I love how you go in depth in real, applicable terms. You pick the mass and size of your bowling ball, why wouldn't you do the same for your axe? It makes sense that this stuff is personal. I guess I just need more practice, because personally, I suck at it.
P.S. I think you've made me realize people probably just mean to say mass. Let the mass of the axe do the work. Right? As in, you're utilizing said mass optimally. There's something very dao about it, swinging without swinging, applying force without forcing.
P.P.S. And the pages at the end! Nice touch!
Gravity applies equally to heavy and light objects. A bowling ball and a golf ball fall at the exact same speed when dropped. An object in motion wants to stay in motion. Therefore a heavy axe hits harder than a lighter axe moving at the same speed...whether swung vertically or horizontally.
@@Master...deBater Gravity does pull heavy and light objects the same, but that doesn't mean that it is the same for chopping.
For example, try to get a light boys axe and grab it on a certain part of the handle (lets say at 28 inches). Hold it at your side and extend your arms.
Now get a 4 or 5 pound axe and do the same, while holding it at the same spot of 28 inches from the bit.
The heavier axe will be much harder to hold up, which means that it will take much more energy when you make horizontal cuts.
Watched this while my 9 year old Grandson Ashton was in the room. By end of the video he was sitting down watching it with me. After I asked if he understood what you were saying. He got it. Well, more then enough of it to understand the concept.
That's great! I've had people tell me that they use my videos for homeschooling. got me to curse less ;)
Good job Steve in exploring this concept of axe chopping effectiveness. I notice that Hults Bruks Axes are making new models with longer hafts and lighter heads
Interesting. I used a probably 2 lb head on a long straight handle for some years and thought I had it all figured out. There's a place for it I'm sure.
Well done Mr edholm - glad to see you back - i find teh old adage of let the axe doo the work is 2nd to the better one of avoid anyone making you do work ./ have a great day.
Which is only slightly better than getting someone else to do the work for you.
Hi, Steven! I think there's one thing that didn't get enough attention. I believe it's what you called "snapping" the axe closer to the end of the video. I learned about it in boxing (with left and right hook shots), but most people know this as the trick that spinning figure-skaters do -- make the radius smaller, and you start to spin faster. The idea is that right before the axe is about to strike, pull the handle towards your body. Any effort expended will go directly towards increasing the momentum of the axe. Of course us newbies would want to use a "Buckstop" to keep our shins safe ;D
Thanks, this has me thinking. I might need to do a little research on that phenomenon and definitely some thinking. I think what I might be doing that relates to the phenomenon you are talking about is to switch from the shoiulder/waist and elbow pivot points to the wrist to accelerate the axe rapidly at the end. While a long handle or handle/arm total combination might theoretically allow for more speed in the head, we have to realize the limits of that possibility. It assumes that the power generated at the pivot point is capable of driving the outside of the system (the axe head) of the moment arm in order to acheive that. So there isn't really a free lunch. The wrists, being closer, are able to drive that system, which is now shorter. Lots to think about there.
@@SkillCult I would also doubt the practicality of that principle, when talking about axe chopping. Because while it in martial art, is an effective way of delivering a fast and forceful blow, while at the same time preserving energy in between, the initial execution, til the landing of that blow, where you would drive an extra amount of force, by using the body properly, in distributing energy from the ground throughout the body, and then execute the last bit of force/tension upon impact.
But using this principle/method in axe chopping, my first suspecion is that it would only be possible to perform effectively by very experienced axe choppers, because you are using an object. And to transfer this principle from the body to an axe, given the nature of how an axe works, with the heavy head and pivot point, is not easy I think. And most importantly the fact that if you apply this "penetration-like" force, which this principle does, to hitting a tree with an axe, much of that force would be transferred back to the body, simply because the mass of the tree is so much bigger, than hitting the mass of the human body, also the human body is a mass in movement, while a tree is a relatively solid/stable (not moving) object.
I have lots of experience with martial arts and almost no experience with axe chopping. So I can only speak from part experience and an assumption of how this would apply to axe chopping.
In case I haven't understood the technique properly which Harri suggest. (Which sounded interesting though) Then please just forget about my comment.😊
I just reread his post and realized that he was talking about increasing the velocity/energy by decreasing the radius of the axe swing at the very end of the swing. So while i did misunderstood it, i guess theres still the risk of reabsorbing some of the force, if you dont manage to relax upon impact when you draw the axe closer to you, and that it therefore still would only be possible for very experienced axe choppers to execute effectively.
Great video professor and you truly are, that was a great learning lesson of course I use the principals you talked about. I use a heavy felling axe and went through a lot of pain the hard way befor I learnd what you covered in your video. Thank you so much for doing what you do with your chanel you teach well keep it up bro
Thanks Beau. Pretty easy to beat ourselves up with either a light or heavy axe.
Hello Steve, a pleasure to see you againg.
Good information in this video but I have to talk about some points. When people says leave the axe weight do the work I understand they are talking about the people who grabs the handle too tightly, swing too strongly and pushes into the cut, I don't know if I have explained it in an understandable way if not please tell it to me. But it can also be understood the way you explain, good job clarifying it 🖒
About the energy formula, you are right same amount of energy can be achieved with different weight axes at the moment axes bite the wood. But when the deceleration part of the swing starts the energy is only a part of the equation. Let's think both axes are identical and the only changing factor is the weight and they are cutting exactly the same wood. When both axes start cutting the wood energy starts to dissipate, at this moment a vital factor not taken in account starts working, inertia. You are not the only one, all the internet places I have seen, listen or read talking about this topic haven't take this in account. Both axes will have the same starting energy but the one with more weight will suffer less energy loss due to its weight (inertia) so it will cut deeper.
At this point personal preferences start to appear, heavier axe swing is more efficient but it takes more strength to work with. If they are exactly identical both axes can be prefered by the same person depending the work to be done. But in the real world heavier axes use to have a (sometimes unused) advantage, you have more material to work with so you can have a broader bit with the same geometry making the heavier axe even more efficient.
Actually I'm quite unfit so in my case my actual sweet point is between 1,75-2,2kg depending in the work to be done. Take in account I'm Basque and for a Basque the efficient type of logcutting for medium or bigger logs consists in using two axes, heavier one for the outside lighter one for the inside.
Great stuff as always Jon. Yes, I agree, the intended meaning is don't shove, just gain momentum and let the axe cut.
Yes, I know intuitively that there must be a difference of some kind in the work done on actual wood by different axe head weights, which is why I pinned a comment to that effect. As I said that is a different discussion. I'm interested in what you have to say about it because it comes from a long tradition and not just recently generated personal opinion. In the end, the place to prove out what works for anyone is in the field with time served.
Great video on axe swinging! I've found a lot of your ideas on axe swinging have translated very well to hammer swinging and helped me understand the subject better, especially the idea that you're basically throwing the tool at the work and guiding it to the target, not forcing it.
Though I find it interesting, one detail that I've heard taught for sledgehammer swinging and found to be true is contrary to your instruction. And that is to not use any parts of your body you don't need to. Where from swinging a sledge I was taught to use every part of my body possible, in thought to spread out the stress of hefting the weight and not stress just a few muscles and joints, allowing you to work longer so long as you have the strength and stamina. Perhaps these two styles of swinging are the crucial differences in how one can make a light tool more efficient than a heavy one, or vise versa.
With blacksmithing heavy sledges have become a necessity so I've learned how to swing a 12 pound weight on a stick with ease, and by the way even with a 12 pound sledge you don't let the weight do the work, ain't nobody got time for that, you throw it at the work as fast as you can control and take 3/8 deep bites of steel. So going into learning to swing an axe I've found heavier axes (4-ish pounds) to be no problem and lighter axes to be very difficult to control. I think I'm going to try this method of not moving so much, and if I can figure it out I'll see if I can make it translate to hammers.
Thank you for sharing your knowledge with all of us!
Well what I mean is not that you should use as few muscles as possible so much as that you should use the ones you need to do the job well or at he pace you need to, but not use any that are not serving any purpose. Also, if you are in the middle of a heat that is only going to last for 2 minutes, you'd better lay into it and you can recover between heats. With a 12 pound sledge, you'd better be spreading out the work! I own a 12 pound sledge. Damn, that thing is brutal. It's been sitting in my buddy's shop unused for about 15 years now lol. Thanks, this might help me refine how I talk about physical efficiency. Whatever you are using and not using, and moving or not moving, It's still going to come down to energy expended and work done. If you move absolutely as little as possible to put the axe on the target, that isn't going to be the best way, but keeping the goal in mind, exaggerated movements that aren't necessary will subtract energy without enough gain.
Great content, found your channel from Essential Craftsman. It's possible, and seems likely to me based on the quote that you're analyzing, that the author was talking about a heavy axe. If so, it makes a lot more sense. It's definitely true that a lighter and higher velocity axe can achieve the same amount of work - and I do think it is more efficient in many ways. Thanks again for making such great videos.
I think really he was trying to say something important in terms so simplistic that it really just becomes an inaccurate statement if taken literally. And he's not the only one.
I have a PhD in theoretical physics from Cambridge and I commend you on your pretty much correct description of what's going on! Well done! I just want to add this to make it a little less hand-wavy and slightly more precise: Don't worry I aint gonna hit you with equations and numbers - although one could do that full quantitative analysis it aint really gonna add much here. Momentum and energy are not the same although the two are related quantities.
The bottom line is, in nature there are two laws governing this: the law of conservation of momentum and the law of conservation of energy. In any physically isolated system, total energy and total momentum remain constant - they are conserved. Here our system consists of man, axe and tree. However this is not a completely isolated system as both man and tree are connected to the Earth, so these conservation laws do not apply precisely to our man/axe/tree system, they only apply approximately here.... but nevertheless, man/axe/tree is a good enough approximation of an isolated system for our purposes here. (btw the laws do apply precisely to system of man/axe/tree + Earth as that is pretty much isolated!!)
So when the fixed mass axe swings, it's the head speed that determines it's momentum and energy (just like a golf club striking a ball). That momentum and energy is transferred into the tree. The tree may move a little but because it is very massive it's velocity only has to be negligible to keep the momentum after the event of axe striking tree to be the same momentum we had before (to satisfy our law of conservation of momentum).
Usually we don't see the tree moving after the impact but there will be vibrations travelling outward from the point of contract transmitted through the wood fibres and travelling all through the tree (and down to the ground). So the axe has plunged into the tree and stopped so it lost all it's momentum and we don't see the tree moving so what happened to all that momentum? answer it's being carried by all the vibrations in the wood fibres. Because our system of man/tree and axe is not perfectly isolated, that energy and momentum is eventually dissipated into the Earth and into the air, some is lost as sound, some as heat through frictional forces of the axe head being resisted by the wood fibres/sticky sap it is encountering as it drives in, some wood chips fly off carrying energy and momentum. But its good enough to say all the momentum and energy of that axe is transmitted into the tree to smash up the wood fibres. Energy is then lost in various forms, mostly via sound and as vibrations of the impact travel down the tree into the ground or back through the axe handle into you and down to the ground.
But the moral is if you can achieve a greater head speed (for your axe of a given weight) you will be imparting more energy and momentum into the tree and that's more energy to slice through wood fibres so gets the job done quicker. If you can swing a heavier axe with the same head speed as a small axe you will be transferring so much more energy to the wood to crush those wood fibres quicker. But of course you only have a limited amount of energy in your body, that is chemical energy your body has obtained from the foods you eat. You will obviously use that up quicker lifting and swinging a heavier axe..... so take a few Trek bars into the woods with you (other brands are available!)
I'll also add that yes all the energy of your swing is transferred into the tree but what's important is the percentage of that energy that goes into crushing the woodfibres compared to how much goes into vibrations of the wood fibres and your axe shaft and how much is lost in sound depends on a whole bunch of factors. These include obviously the sharpness of your axe, the type of wood your are cutting, whether its dry dead wood or very sappy wood, how well the density of the wood fibres transmit vibrations and even your technique such as how hard you are gripping. To minimise vibrations running up your arm, shafts of axes (amongst other reasons) are made of hickory which does not transfer vibrations so well (have you ever heard of a guitar made of American Hickory?, no coz it's a poor tonewood) so hickory is good at stopping those vibrations running up your arms on each strike (as well as being super strong of course which is the main reason it's used for handles).
Kinetic energy is proportion to mass times time velocity *squared*. Accelerating objects are also more stable. These are both important to an axe's performance. The best axe swings take both these in to account.
Mass and velocity do not have a 1:1 relationship in the kinetic energy equation. Actually the formula is K=1/2MV^2. Velocity adds much more than mass. At some given mass though the axe head becomes more stable and adds to the economy of the cut.
That is kinetic energy not momentum, and this video was referencing momentum.
You are right on ENERGY IMPORTANCE here, and it was discovered nearly FOUR HUNDRED yrs. ago by Sir Newton ! And the V is your (ARM+HANDLE)*ω of axe make the linear velocity acc. to his theorem. ω is for angular velocity here. Steve real observation was then right : axe velocity makes much more than its mass in a whole cutting process. Acc. to me, the proper mass comes from your own axe preference, just is made be practice ! Swinging axe perpendicularly instead of traditional way is interesting skill worthwhile try.
There are two factors at work here. The first is the equation for kinetic energy, which is E(k)=1/2mv^2. Kinetic energy equals one-half the mass multiplied by the square of the velocity. As you can see, velocity has a much greater effect on the amount of energy in the moving head of the axe. Because Force is also equal to mass multiplied by acceleration (change in velocity), F=ma, we can see that the smaller the mass, the faster we can accelerate the axe head, and therefore the higher velocity we can impart to it.
However, this does not tell the whole story, because what we want is to impart that force to an object so we have to think about energy transfer, and how that is affected by the ratio of the mass of the axe to the mass of the target. The greater the difference between the mass of the axe and the mass of log, the less efficiently the kinetic energy of the axe is transferred to the wood. So, the more mass in the axe, the more of its energy with be transmitted to the log.
What this means is that in general, for the best efficiency, you should use the heaviest axe you can comfortably use for the continuous time period in which you expect to use it, since in most cases, you will be hitting a piece of wood more massive than your axe.
Please show us the rest of your library. Wildwood wisdom is a great book.
good idea. most of it's packed away right now.
Love the geek fest (I'm an engineer). To articulate your point: P=M x V. (P=Power or Work). Mass and velocity are equally important. Any reduction in mass can be overcome by an equal increase in velocity. So exactly like you say... if you can effectively land your swings at a higher velocity, you'll get the same results with a lighter axe
Interestingly, the reverse is also true: You're putting the same amount of power into the axe (Power in = power out minus some air friction, etc) with either weight. But you'll get a higher velocity with a lighter axe wth an equal amount of power put in ;)
m*v is not power, it is momentum (little p). Power is energy/time.
power = momentum? you don't sound like an engineer to me
I didn't know if the energy input would actually be equivalent. I guess there is also the question of not just calories burned or however you would measure that, but the fact they are different kinds of work, increasingly, as you go from light to heavy. Also, even though the energy delivery via momentum might be the same, it seems intuitively that a lighter or heavier head would interact differently in various materials. I'm not sure how much it matters in a practical sense, since at some point you end up arguing preference and there must be an insane number of variables.
There is no "or" between Work and Power ( W = P x t ) Work is what Power does over a certain time.
At constant Force or Work ( W = F x distance) the lighter ax gets a smaller momentum as halving the mass doesn't double the speed. If weight does the work (vertical stroke), the heavy ax gets also even more Force.
Momentum is biased by mass and mostly weight. Where precision isn't.
my hed herts
Nice video it was like a mother earth news seminar, I do prefer the skinnier handle on a restored Norland axe to the fatter, bulkier on a couple of the Swedish axes I own
Thanks for the video Steven,
I'd be interested to hear your opinion on the balance of an axe. I've read that the weight should naturally be in the head of the since the haft is used to deliver the head to the work; which made a lot of sense to me. In other words, the balance point should be as close to the head as possible for an ideal balance because energy is wasted when it goes into accelerating mass that wont impact the work. Some people say that it when it balances, the head should be horizontal, or parallel to the floor. This means the poll is the same weight as the bit, which prevents wobble during the swing, or increases accuracy. Some people say they don't think about and just use it.
I recently re-handled a 1.75 lb head with a 28 inch handle and it swings poorly versus my 2.25 lb head. I'm removing more material from the handle to raise the balance point closer to the head, and then will be re-profiling the bit to get a better balance out of the head to test this out. Again, if you have any content about this I'd be interested to see it.
I don't really feel qualified to speak much on that. Certainly having the weight shifted toward the head is important, but how far I couldn't say. Traditional European axes are weighted toward the front by design. The balancing by adding a large poll is generally said to be an evolution in the right direction. Double bits are favored primarily for that reason too. It obviously does make some difference, and I don't favor very out of balance axes. That said, the Basque use very front heavy axes and are extremely good with them, and the forests of Europe were destroyed with front heavy axes, so.... As far as length and thickness of handle, I just make the handle the thickness I want to be using and the rest falls where it will.
The limiting factor in this is the human. You want the heaviest axe you are able to complete the job with. And, the job has quite a bit to do with accuracy - to knock out good chips you have to hit your target +/- 10 degrees and +/- an inch or so, and you might need to do that, oh, 10,000 times a day for weeks on end without injuring your body.
And, the LENGTH of the axe is important, too, because the handle effectively extends your arms, lets you move the axe faster and put more energy into each hit. But, a longer handle lowers accuracy and needs more clearance, etc.. I have an axe that I can hold and tuck in my armpit. I've never weighed it, but it's small. I still wear out swinging it for an hour.
interesting point in contemplating the balance between weight and speed: in ballistics, if you double the weight you double the delivered energy, but if you double the speed you quadruple the delivered energy.
Yes, that's been pointed out a lot. Do you know what the cost in energy is though for a given momentum arrived at by either route? Also, there is obviously a limit to our ability to generate velocity, no matter how light the axe. That is one of the hard limits on either side, another being how long we an sustain the use of a heavy axe, or use it with any skill if it's very heavy. That still leaves a pretty large area in between.
And tool geometry is a factor. And long vs. short lever arm. Not to mention ergonomics. Whatever works, works, i guess?
Bullet ballistics about sum it up. Great video.
So many ways to relate to this concept. It makes me think of similar formulas like volts x amps = watts. I hammer a lot so it's easy for me to relate it to that. Martial artists might liken it to punching or kicking. We all have a different tool kit with our body mechanics to work from. We have shorter or longer legs and arms, different levels of strength that are variable in different parts of our bodies. Most people have most of their muscle strength in their legs and butt. Any time you can connect that muscle mass to the work you are trying to achieve the less tired you get and the more power you transfer to the work. Obviously it's not always possible. I've noticed that when I bend my knees a little and consciously get my legs more involved when cutting with the scythe or an axe that I am able to cut more and get less tired. It just flows better. I agree completely with you that to begin with you have to find your happy place where you can hit what you are aiming at and work to increase power from there. Without accuracy you are wasting effort. It really boils down to as with any skill, theory is important, but training and experience, time spent doing the task, make the biggest improvements. You also mentioned strategy, which I assume you mean how you design your chip removal, is key to efficiency, but I suppose that is a subject for a different video.
Great comments. yes, volts x amps = watts is similar in that there are two variables that can be changed to add up to the same useable value. What interests me most in martial arts is how people can use the same strength and energy more or less effectively/efficiently with small changes in body mechanics, and the same economy of motion and conservation of muscle use that I'm trying to communicate. I think that stuff is hard, if not impossible to teach. Like you said, you can explain and theorize all day, but it's all about time served. Strategy, to me is primarily angle of cut, cut placement and order of blows. The difference between executing that well or poorly can be huge and of course a lot of beginners don't even have a plan. Strategy - Tool - Accuracy - Technique - Efficiency !
A long while ago I was taking a karate class, and I was practicing the first kata, and after long practice a couple of times (and only a couple) I threw a punch in the right manner, the punch was rooted through my core, down into my butt an thigh, all the way down into my foot... I felt the punch in my foot and it went right down into the earth. The timing and posture were very hard to perfect, but I can't imagine striking someone with such a punch. The trick is to perfectly sync several simultaneous rotations within the body, if all those rotations are aligned right at the moment of the apex of the strike, and the strike is rooted through those rotations down into the earth, the force is insane. I imagine snapping the axe just right is a similar experience, but I've never done it. Wish I had the wood and a body to practice with.
*No reverby ethnic flutes were harmed in the making of this post.
It's actually more analogous than that. Voltage is potential force, like the weight of the axe head that does nothing until something occurs to cause current to flow in the circuit (amperage), like the speed that you throw your axe resulting in work being performed, which is wattage and chips flying. You can increase work performed by More potential force as in more voltage and a heavier axe or more current in your circuit and more speed of your axe. And just like chopping with an axe there are limitations and trade-offs when increasing one or the other. It is after all a geek fest, no?
yes, but try to explain all that to any one person and see if they can do it. There's more going on than even the person doing it can understand or explain. Think of boxers who study that stuff for years and practice endlessly, but some get it and some don't. There are so many factors involved. With an axe we have the advantage of the work isn't trying to get away from us!
Perhaps we should have boxing matches with axes? Prolly bad idea.
@skillcult Mors would be proud of you!! You should see if you can make it to the global bushcraft symposium this June 10-14 2019 in alberta!!
I can just make it to town to get supplies usually. I haven't really traveled anywhere in years. What I'd like to do if I could is go spend some time with Mors and somehow document or translate some of his axe related knowledge.
@6:50 I laughed out loud. Perfect demonstration of concept 😂👍
Axe ballistics ( external and terminal ). Love the stump speeches.
Thanks for your insights, l may be retired but we are never too old to learn
Interesting
I totally understand the physics
As a Scoutmaster, I teach scouts how to use axes.
I want them to feel the weight of the axe as they swing it
It is a sensory experience
The correct english word is feeling the heft of the axe
But in plain english you feel the weight of the axe making its arc before it hits the wood
So using weight of the axe is not scientific physics, but how it feels
I hear you, and I think that is a good way to teach aim too is to feel the head as it swings, like that is the point of attention. The issue I have is with the idea that the weight is allowed to do the work, which can be misleading. Understanding that it is actually the momentum of which that weight is only one factor, can lead to better application I think, and especially better transitions from light to heave axes and back. Thanks for commenting.
The 2 3/4lb hults bruks axe may be making its way to the U.S. Bucking Billy was saying Hults is bringing the Arvika 5star 4.5lb to the states in oct. maybe they will being the whole line. And on another note. Your axe handle on the council axe is only slightly thinner than the octagonal handles Ive been using. Keep up the good stuff
That would be cool if it's affordable. I'm curious about that axe. Isn't that handle cool how saturated it is? I loved that handle :)
I know of a few USFS trail crews (mine included) that use the 4.5lb arvika 5-stars for trail clearing in wilderness. they don't chop worth a damn until you spend a few hours putting a decent grind on them, but they are excellent axes. very hard, very durable steel. hard to file, but they keep their edge for a long time without being brittle.
in the right hands, an 18" diameter lodgepole only takes a few minutes to chop through at an easy, "all-day" pace.
That's very interesting. Especially since you have to pack them. I'd like to see how you guys grind them. What handle length? Make a video! :).
I agree with Stevie here, let's see it!
i ground mine with my 9031 makita belt sander with a jig I made. you can see a video of it being used on my page, if you want. i thinned out the shoulders quite a bit, and removed quite a big of the cheeks behind the bit, before putting a fairly long chisel grind (1.25" and around 15 degrees) and a fairly steep secondary bevel (around 30 degrees) to give the bit some toughness.
we run these axes on 32" handles, but a 30" would be good for shorter users. Ill see about making a video when i get back from my vacation.
The formula for kinetic energy is (1/2)mass x the square of the speed ( E=0.5M * (V*V), meaning, if you double the weight of the axe, you are NOT hitting twice as hard at the same speed, its only 50 percent harder impact for double the weight . If you double the speed you are quadrupling the energy of impact. To maximize impact energy you should select the axe you can swing the fastest, then go up in weight until you your swing speed decreases slightly. This is the same technique you would use for any kinetic force tool, such as finding the optimal size baseball bat or sledgehammer.
This formula also governs the relationship of horsepower to 0-60 times. If you want to cut the time in half you would need to quadruple the horsepower, not simply double it.
As far as the vibration into your hands, the effect is the same as when striking a baseball with a bat. If you make perfect contact on the "Sweet Spot" you will feel virtually no vibration on your hands regardless of how hard you hit the ball. The sweet spot is located approximately at the point on the bat about 7 inches from the end, at this location the kinetic energy in the moving bat above this point and below this point are equal. Any higher or lower contact and there will be a severe vibration into your hands as the bat is attempting to pivot around the ball or in front of the ball and the only thing to oppose this force is your hands.
Aiming with the sweet spot on the axe also helps to minimize vibration, the preferred impact zone should be from about the centerline of the blade, down to the beard of the axe. Most axe heads only being about 3 inches tall make it pretty hard to end up too far from the sweet spot, but practice aiming with the beard of the axe is always helpful to maximize impact energy and reduce vibration.
Let's try this out. Say a 1 kg mass xe moving at 2metres per second K.E. = 0.5 X 1 X 2 X 2 = 2. Let's double the mass. K.E. = 0.5 x 2 x 2 x 2 = 4. To me doubling the mass while keeping all other variables constant means doubling the energy. You are free to disagree.
Another brilliant video.
Centripetal force = mass x velocity^2 / radius. Notice that velocity is exponentially more important than mass. However, there is also a penalty for the radius of the arc. Of course the longer the axe handle the faster the swing, but finding the sweet spot between a really long axe, and a really fast axe (at the circumference of the arc) is ideal.
thank you for metioning the cost. That is the key, COST. What is the cost. Knowing that speed is more influencial that mass doesn't tell us what the cost of that speed is. Also, as you say, the cost of that larger radius on longer handles. IF all that could be calculated, I feel it would be of dubious practical utiltiy.
Very well said Steve!!!! Great video!!!!
thank you.
It seems like he did know exactly the principles you're talking about but was over-simplifying and over-generalizing it. Especially if he was into heavier axes like I am ( no idea if that is true or not), the statement makes more sense. I do feel that the heavier the head is the less ability you have to correct a misaligned cut during the swing, so the more you horse it the less control you have. When I look at video of myself bucking, it kind of looks like I'm just letting the axe fall all by itself, even though I know that isn't the case. I think another way to say it is if you have a light head and a heavy one and you give them the same momentum, the light head is going to be traveling a hell of a lot faster. So your really adding something like the same amount of energy into the cut.
Yeah, it's not necessary to understand it intellectually to do it or "understand" it physically. It's just practical wisdom and you can sort of gather something from it to take home, but it's not accurate. You can let the weight do more of the work with a heavier axe, but it's still on a spectrum where without velocity, there is no action. The next question is how does each body interact with the wood when it hits given the different masses. I don't know enough about any of it to know, but I'm assuming that they equation wasn't created to predict how varying weights of axe heads will penetrate a piece of wood ha ha. Someone also left a comment recently that increasing velocity is more effective than increasing mass. Not sure what to think of that.
It would be really hard to prove though. I feel like with axemanship, there's so many variables that being able to tell that a faster light axe is ultimately a better cutting tool than a heavy slow one would difficult. I'd think you'd need to build some kind of chopping robot and uniform wood to chop to eliminate enough of the randomness to be able to actually measure which cuts more efficiently. Which would be insane, although I'd totally watch that video.
Yeah, that could be interesting. There's some comments on here that might shed some light on that question.
I think your body type, strength, fitness level, technique, experience level and even your personality all play into that equation. Some people cut better with a lighter axe and others do better with more weight. What works great for me is not necessarily going to work for you.
I mean I wouldn't want people to know where I'm chopping people up but you do you dude
The local McDonalds patrons are safe. I have lots of trees to chop down.
FOR NOW!
I find 3 pounds is my max weight to swing maybe 3.25. Then handle length comes into play. Something to be said for the energy used to deliver the axe and the relationship to accuracy. Too much energy (for your level) and aim will suffer, as will not enough energy can't direct the strike. Handle thickness can play into this too, in relation to fatigue and balance of the axe and grip, just struggling with a good grip can cause fatigue. Good point on not following through the cut, bring it to the point of the cut and rest. 18 minutes can go so fast.
All great points. Accuracy first, power comes later. Glad it went by fast. I worry about that, but it's hard to make short videos and not cut a lot out. I watch videos and feel like I'm 15 minutes in and they've barely said much and It's only been like 4 or 5 minutes! Hard to know how others view stuff. I try to edit hard to remove small pauses so that it seems like things are always moving along. I think that psychology is important. It takes a lot of time though. Stephen King said "kill your darlings", meaning, write to serve others and the story, not your wants and pets. Easy to say, hard to do.
Some videos it takes for ever for the point to come across, like in the last moments.(not typical in your videos)fun topics help too. This one cuts right to the chase and holds it through the video.
Yeah but Stephen King was under contract to try to sell novels, we all like what you like to talk about, else we wouldn't be here haha.
Thanks Edholm!
Mr. B returns!
Excellent videos man. Question for you. I'm thinking about getting an axe that comes with the option of straight or curved handles. What are the pros and cons of each?
As far as I know, curved handles are a somewhat inadequate attempt to compensate for a poorly balanced axe head design in poll axes. The curve at the end changes the relation of the cutting edge to the wrist position too, which may have some real or imagined benefit. Otherwise, if there is any advantage it's small. Straight handles are stronger because the grain is violated less.
The only way to determine what ax style, weight, and haft lenght works for a person is by trying each for a long enough time to evaluate properly. Most will only use one ax, so the first one they try will be the best and after a while they will go to almost any lengths to justify their opinion based on limited experience.
I grew up in a timber/lumber family so was exposed to many axes. I used most at one time or another for extended work times. As a result when I bought my first first new ax at 12 years old i was already familiar with many. I chose to spend my hard earned money on a double bit Kelly true temper three and half pound 36 inch tool ( I still have and use it often at 74 years old ) but later determined my particular sweet spot is a five pound double bit with a 40 inch haft.
I am more accurate with that length than with 32 inch hafted axes. I own and sometimes use short haft axes for one handed carving type work but even a lot of that is done with the larger double bit axes.
I have found myself to be more comfortable with straight hafts no matter what the ax head pattern. I think of the haft as being a string that I use to throw the head at the wood more than something to poke it along. A heavier head may require a slower start of the swing but when the edge meets the wood the speed is close to equal.
As stated every one is different, I relish the feeling of my whole body doing part of the ax swing rather than just arms and shoulders. The total energy expenditure is probably similar but spread out may be less tiring after a whole day of work.
Thank for the comment. Always good to hear from people with long experience, or professional experience.
So, I’m also gathering, that a lighter axe would be easier to control? I guessing that’s a safe assumption?
I think that it somewhat true, but that has to be balanced against swinging faster, which can definitely throw your aim off. Imagine trying to use a 1 lb head on a 28 inch handle to cut down a tree, you'd have to swing ridiculously fast and at some point it becomes clumsy. That is one problem with the "forest" axes. They can do a lot of work, but they take some getting used to in order to be able to swing them fast enough and not get clumsy. Once you do, they are surprisingly capable, but it's a little bit of an investment to spend the time.
SkillCult Makes sense. Where’s the happy medium for a beginner? I have a lot of knife knowledge, but axes...not so much.
SkillCult BTW...thanks for taking the time to answer. You’re one of the few willing to take that time on older videos.
I'm not sure I am ready to answer that, but I think it might be about 2.5 lb to 2.75 lb, but unfortunately uncommon sizes. 2.25 lb is okay, but can cause some to swing excessively hard before they should. That is what is very commonly availble now. Obviously that would vary by person too.
Great video.
Thank you, it was a bit of a project.
Great vid < from the heart ! God bless brother
Cheers!
If you half the axe heads weight but double the speed you get twice the impact given same handle length/edge geometry :).
So people are saying, but what about the difference in cutting ability of a larger v.s. heavier mass hitting the same piece of wood? Also, we are talking about a somewhat arbitrary value (speed) right if energy input isn't calculated?
So then the question is whether it is possible for the average axeman to swing such a head at twice the velocity of the original head weight? How much faster can a light head be swung? I don't think that its actually anywhere near twice the velocity, especially over a long work session. My own experience with light vs heavy heads is the total amount of cutting done is fairly comparable- its a wash.
Mathematically speaking, it should be a wash. I think it comes down to a lot of extrinsic factors outside of the actual swinging and striking of the axe.
So many variables and hard to prove with theory alone. A lot of physics principals are raised here, but at the end, who can really prove what, and how much does it really matter. This treatment was intended to be shallow, and it's ill informed because I'm under educated by modern standards (thankfully). My main goal was to relate a principal that could help people progress, without misinforming anyone. The large v.s. small is up for debate as to outright energy efficiency and it's an interesting topic, but it's only so interesting and the place to prove anything to ourselves is still in the field. I'm looking forward to that process more. The part about the inertia of a heavier head possibly being more effective against a still mass than a light one regardless of the momentum value is interesting enough that I might think about it more.
Say Heah, I sort of agree with that part. Of the weight matters. I find it true with my 17" Hultafors Bruks Agdor Hatchet vs. my Gransfors Bruks Small Forest Axe. First it's more compact and yet it weighs a 1 3/4 lbs being compact and I can wear it in a Axe Holster I made my 17" Hultafors Bruks Agdor Hatchet my favorite Bush Craft Hatchet. I bought it on closeout when Hultafors Bruks changed Ranges. It came spot on, I got lucky. It didn't come as sharp as my my Gransfors Bruks Small Forest Axe, But in no time it was as sharp and it holds as good of a edge retention as my S. F. A. Solo Yeah, it became my Fav's Bush Craft Hatchet. Infact I love teaming it with my Modde Rodent 6 that now looks like a Ratmandu on steroids. It too is one of my Fav's All Time Knives in the 6" size (in carbon steel). I could neck carry my Mora 519 or now my new Cold Steel Ultimate Hunter Folder. Sort of my Wannabe Nessmuk Trio, heh heh heh. I also noticed this concept in my Custom Made House Axe a Canadian made for me. Maurice out a Vintage Iltis 2 1/2 lbs Oxhead Head on a 19" White Hickory Handle. The fact it's a very thin cheek head with a wide face (5 1/2" ?) It still splits fantastically. IT'S THE WEIGHT !!!. The only problem was I had to make a special harness to carry it to our place, but it's all good now. Infact the guys that laughed at first at it, now are the first to want to see it. Yeah, It's very compact, but I have no problem felling a small tree with it either. So, Yeah, I have no regrets having it made. As far as our Cold weather Axe, I originally wanted a Husqvarna All Purpose Forest Axe, But it came defective. The manager insinuated I wouldn't be happy and find fault with the replacements too, so I was sort of pushed to get the Iltis Ochsenkopf Axe OX 620 H 1257 with the RotBand Plus. After using it, I fell in love with it. It's a real good Chopping Machine. It has the RotBand Plus which is a Steel Plate that goes over the eye then is screwed into the handle. It also has a Steel Sleeve to protect the handle for a over bite. But boy does it chop again it's a 2.7 lbs head. A little heavier than I first wanted fearing it would be too heavy to carry into the bush. A harness settled that in both cases. Oh, On my Cold Weather Solo Trio's, I settled on my 24"Council Wood Craft Pack Axe with the heavy duty sheath and sling. A lovely piece of kit. It's made out of the 5169cCarbin Street and it's Outstanding. With my Piggyback Rodent 7 and my Rodent 3 in a Baldric Carry with my 24" Council Wood Craft Pack Axe and my Agawa Canyon 21 Boreal Saw and my Gerber Multi Tool, I fear no even, Ofcource I carry added protection, Yeah, Paul'ies Bad, heh heh heh. But "Aparro" is my Motto. If, I go with a Basic Trio Carry in Cold Weatger, then it's my Modde Rodent 6 that looks like a Ratmandu on steroids, with my 24" Council Wood Craft Pack Axe with the heavy duty sheath and sling and my Agawa Canyon 21 Boreal Saw and my Gerber Multi Tool, plus my either Mora 510 as my Neck Knife or my new Cold Steel Ultimate Hunter Folder. I also can use either my C. S Black Rhino Folder or my C. S. Medium Vaquero or either of my a Gerber Gator in the 420HC or 154 CM. Yeah, Nessmuk had a point to carry a Trio like this. I just think adding a saw is a good idea for me. It saves alot of energy. With even a Kodiak Gearsling I can attach all this gear without a problem and still move quickly through the bush. That's why this weekend I eliminated bringing a Hatchet along and just a Summer Long Knife instead. I brought my 3V Skookum Bush Tool and teamed it with my Ka-Bar Johnson Adventure Parangatang a great Machete type Tool. It's made out of the 1095 CroVan Steel which holds a excellent edge retention. It's a 14. 125" blade and .190" thick. The two even match nice in color. Yup I added my Agawa Canyon 21 Boreal Saw and my Cold Steel Ultimate Hunter Folder and my Gerber Multi Tool. I use the Awl carefully to untangle the and to remove hot pots from the fire. A real handy Multi Tool. Oh, also to remove shortie from my Cigar Mouthpiece, heh heh heh. So, Yeah, the Point Is, Weight Matters, in my opinion.,,.p
Jesus..
Dang it man, ya made me think! It's Friday night, and that's totally uncalled for. 😁
Now I'm wondering if a light head on a longer handle would be worth trying, or at what point is the loss of accuracy to become a problem... arrrggg... that ones gonna bounce around in my head for a bit. Tomorrow might turn into a test of weights and lengths against some firewood.
I remember Mors Kochanski telling me that native people would put light heads on very long handles, because that is what they could get. It's just going to come down to whether you can swing it accurately or not. There is also the issue of just practical handling in the work you are doing. I used a head that was probably 2 pounds on a pretty long handle once for some years. At the time, I thought I had it figured out. Now handling is very important to me and I like the old rule of a multi-use axe being about palm to arm pit. Hope you sleep well! muahahahahahaa...
Ive try a 25 inch axe with a 2 pound head and a 32 inch axe with a 3.2 pound head and i prefer the 32 inch , more safe and more powerfull , more the handle is longer and more a axe is safe . But its my personnal preference ✌️
That is definitely true about safety and short vs. long axes. 25 inch is the shortest I consider acceptable in a serious multipurpose axe.
Length affects the type of work too though. I do a lot of tree processing from start to finish and I find that a long handle gets in my way a lot more than it helps with anything. especially in bucking on the ground, where I find long handled axes very annoying. but also limbing.
Please take no offence, you have really done a good job here, but it's even more dramatic when you get the right formula ... Energy equals one half (mass times velocity SQUARED). If you double the mass and keep everything else equal you double the energy and the potential work that gets done. However, if you double the velocity and keep everything else equal, you QUADRUPLE (4x) the energy and the potential work that gets done. Like you mentioned in your video, the trick is the engine that drives it all. And accuracy is key to efficiency with an axe (if you can't hit the target, you're not going to get the job done.) An individual who wishes to optimize their effort with an axe, needs to find the greatest speed that they can still be accurate and not get overly tired too quickly. Handle length will be a surprisingly large factor here (ability to accelerate the axe and still maintain control, longer is faster but there will be a point where additional length will start to slow it down or create excessive physical strain.) Then use the heaviest axe that, again, doesn't tire them or slow them down. The length of time that the pace needs to be maintained is also a factor (marathon runners don't sprint all the way to the finish line.) Everyone who diligently seeks the answer will find their own unique solution and like you mentioned, given experience, body type, physical skill and fitness, and any other changes that may occur over time, that solution may also change over time.
Love the videos ... keep er up!
I thought about looking up the equation, but I didn't bother, because I just don't really care that much. I wouldn't know and didn't actually even mean to write it the way I did as a real equation. I barely graduated high school and for practical purposes didn't, so I suck at anythnig math like. I'm not interested in calculating anything, just the basic principal. I just figured this out myself splitting wood and my neighbor told me that I was describing the mass - velocity - momentum equation. Many people have pointed out that velocity adds more than mass, but that tells us nothing about energy used in the system does it? I haven't heard anyone able to speak as to how that affects real life work, where the currency is energy expended to get that speed or move a heavier mass. Calculating that seems like an impossible undertaking, but maybe there is a way it could be done. Another thing I brought up in my pinned comment and that others have brought up is that a larger mass must behave differently than a lower mass when striking a given object. It seems intuitively that would have a significant effect on penetration, or is that totally synonymous with momentum? I'm really only interested in how these things play out in real life. Perhaps the seemingly uncanny ability for small axes to do a good amount of work is really dependent on that quadrupling effect, but to figure that out, you'd have to start clocking speeds and weighing things and making calculations, which sounds about as fun as going to the dentist, just cheaper lol. And again, that tells us nothing about energy expended right?
@@SkillCult No need to apologize for not being good at math ... the average person needs to be able to balance their bank account and figure out how much 2 pounds of apples are going to cost at $1.50 a pound. I think that you are aware of these things through experience and in many ways that can be better than knowing the math. Just for example. Lets say a 4 pound axe swung at 100 mph penetrates 3 inches. You, from experience know that if you boost the speed up to 120 mph you can get the same penetration with your 2 lb. axe. It's actually the same as what the equation would calculate. You are doing the same work by trading weight for speed because in your case/experience speed is the "stronger" variable. The math does support your conclusions.
@@corwinchristensen260 Great conversation. I love this stuff.
I disagree that you can’t change the weight behind the blow without changing axes. When you let go of the axe it has the weight of the axe behind it only, but when you hold on through contact and get your own mass behind the blow you can manipulate the mass variable. I’m no experienced chopped but it seems you’ve deemed this use of your own mass inefficient. Maybe so, but think about a punch, is it the weight of the fist, the arm or however much of your body you can make connect through muscular tension? I think the latter.
Thanks for commenting. In chopping wood, I'm sure you can add some push through force to the blow, but I don't think it is a lot. In practical chopping and splitting it is a mistake to do this to any extent though as gripping the axe handle tightly transfers much more shock to the hands and arms than a lighter grip. So, the extent to which it is actually possible I see as minimal and using it is ultimately poor technique. Whether you could call this mass or not I'm not sure. It may not really matter and is probably a combination of mass of the body and muscular force against a fixed object, which may be somewhat functionally equivalent in that they are both ways to increase pressure. Regardless, both suffer from a similar problem, which is the efficiency, practicality and sustainability of applying that pressure. But my other problem with this common argument (which often uses punching as a comparison) is that I think the axe handle gives a mechanical DISADVANTAGE, if anything, when it comes to applying pressure and/or weight (whichever or both) to the head. If you were to place the axe head on a scale and hold it at the end of a long handle, I think you would find it unpleasant and ineffective to apply pressure. if the axe is roughly horizontal, you can only apply pressure to the end of the handle and the end of the handle just wants to go downward unless you stiffen what we could call the handle/hands joint, which is done with our muscles, which requires the expenditure of more energy. If you tip the axe up more and more, you might find that you can apply pressure through the handle in an increasingly straight line, but it will also increasingly be applied to the top of the head or corner of the axe, not the bit. And to do this, instead of just stiffening the hand/handle "hinge" we have to grip the axe handle tightly, to our hands don't slide down. Just for understanding's sake, if you put the bit at the top of the axe, then we can put it vertically , and push on the handle like a bark peeling spud or chisel. Now the muscular power and body weight is driving straight through and the body mass and muscular pressure factors have become increasingly relevant. But at what cost and how good is it? Imagine a tamper for compacting earth. We don't build it light with no side "Tee" handles, grip it tightly and slam it into the ground with a hard girp and follow through with our weight. That is both inefficient and hard on the body We build it very heavy, with side handles and pretty much lift and drop it. Our work is the lifting. by taking an axe of a given weight and building it more like a long chisel essentially, we have completely lost the mechanical advantage in the tools design, which is the ability to increase speed with little effort, via a pendulum effect. In physics it's called a momentum arm. So for those reasons I find applying pressure by muscular force, or weight, through the end of a horizontal handle inefficient, very limited and hard on the worker. The punch analogy seems to make sense until you start thinking about the mechanics involved with applying force or weight through the angles involved in chopping, and through what is a very weak joint at the handle/hands juncture, which essentially want's to fold when pressure is applied. I think you would find that people who chop or split a lot of wood for a long time and are essentially forced to become proficient and conserve energy, will use less force and more speed over time. The physics and angles of a punch driving through from the back foot anchored on the floor is very different and the joints involved are all built in and relatively efficient I think compared to the handle/hands joint.
@@SkillCult that makes sense, thanks for the detailed description. keep the great content coming please man, im really learning a lot of useful stuff from your channel. my wife and I are finally about a month from moving out to a little acreage from the city and i cant wait to start applying some of this
I ended up writing a blog post draft this morning about that stuff, so thanks for the poke :) I'm glad to hear you are inspired. Best of luck with your new place and projects!
Love it! 👍🏻
Great content... like the difference between a Louisville slugger and a wiffelball bat ...I am much more accurate with a lighter axe .
I don't want to pick at you for the sake of it. Mass X velocity = "Embedded energy" did get my particular breed of goat. Much of what you say is quite sensible but: ... Kinetic energy is 1/2 X mass X velocity X velocity. Energy and momentum are not the same. A bullet has a small mass and a high velocity. The emphasis is on the velicity squared. Double the speed and you have 4 times the energy but only twice the momentum. There is an optimum handle length depending on the size, shape and purpose of the axe head as well as the size and shape (ie fitness) of the person swinging it and an optimal head mass for the task and person and handle length. My golf clubs have an extra inch in the shaft and they were better for me (when I was 20). Not so sure now, that's life. A 4.5 pound axe is the preferred weight for competition axemen and they swing it fast and furious for ?.? seconds. I am not that fit nor that strong. I have a 6 pound greenwood axe. You can only make one mistake with it: picking it up.
I'm not that interested in the math part of it. I didn't even know this basic principal until I figured it out while splitting wood and told my neighbor and he as like "that's momentum" what is relevant to me is more the energy cost accounting there are probably 20 or more comments like this, but almost never, maybe never, any discussion of what the energy costs are for said increase in speed, which is the thing that actually matters. The full picture is so complicated that I don't see much point in breaking it down. I don't see a place where any equation matters much, except to the extent to which is can inform practical use. The point of this video was to address a common misconception that leads to functional confusion and highlights what people can actually do to use any given axe well, by not choosing oversized axes, not trying to overdrive or underdrive big axes and concentrating on relaxed speed for small ones. The main benefit I think is the idea that if you can create speed, you can make a small axe do more work than one might think. People think of speed differently than just swinging "harder" and I hope are more likely to learn a more relaxed and efficient fast swing. thanks for the input.
@@SkillCult I just saw the comments from Ruster Cat from 2 yrs ago apparently. He is saying basically the same thing as me but heat and sound are forms of energy so the energy of the axe head goes in to splitting the wood as well as heat, sound and deformation. An examination (and it can be measured) of how much energy is "lost" ie transformed to other types and how much goes in to deforming the wood and breaking off chips for various weights, speeds and wood types would reveal which type of axe is best for which wood (and person) type. The point I was trying to make with "double the speed" to get 4 times the energy is that speed is in some sense more important than mass as doubling the mass does not give you 4 times the Kinetic Energy. The equation tells you that. Let me quote you "almost never, maybe never, any discussion of what the energy costs are for said increase in speed, which is the thing that actually matters". I was trying to address that very point. The energy costs are proportional to the increase in speed squared. Think of the amount of kinetic energy in a bullet. It comes from the velocity to a greater extent than the mass. Garry Player was (I think still is) an outstanding golfer who said he could hit a golf ball further at 70 than he could at 40. No he is not stronger, his technique is no better and he is not more flexible though incredibly fit for his age and a genuine golfing legend. His observation was the benefit has come mainly from the incredible advance in golf club (and ball) technology which has added dozens of metres to a long drive. Here is wikipedia 1976 - Evan Williams, 307 yards: 1986 - Art Sellinger, 311 yards: 1996 - Jason Zuback (🇨🇦Canada) 351 yards: 2006 - Jason Zuback (🇨🇦Canada) 368 yards: 2016 - Joe Miller (🇬🇧 UK) 423 yards. The money in golf and the fact that rich old guys will pay more for a club that gives them an extra 5 yards means that it is financially viable to conduct the experiments, do the maths and market better golf clubs. Not a lot of money in making axes compared with golf clubs so not a lot of progress. Yes it's complicated but if you want a better axe for a specific job it can be done but the only thorough way to describe the process is if we (to use American idiom) "do the math". I must say "I don't see a place where any equation matters much, except to the extent where it can inform practical use." is saved by the second half of the sentance. I would say that the equations governing the distribution of energy do inform practicl use in practically every aspect. Mathematics is the language we use to describe our physical world. "How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality?" I don't know either but it is true and I am in good company. It is also true that I was not the first to say this.
@@SkillCult Seriously I don't want to pick at you for the sake of it. You make interesting videos and raise interesting points.
If you are calling it "embodied energy" then you're really talking about kinetic energy whose formula is 1/2mass times velocity squared . that clearly shows that increasing velocity has a greater effect than increasing mass.
Thanks Mark. I need to think on this some more. Various comments here raise a lot of questions about mass and velocity, mass behavior and energy input to the system. Mostly though to figure the efficiency differences between light and heavy axes, which wasn't my intent here, though I think it's an interesting topic. I think any guy with some axes he just happens to have will still find how to use them well and weight preferences by application with only a small amount of theory.
+1 Mark!
This is exactly my recollection as well. Importance of the weight is more or less marginal.
There is however a high importance of the efficiency vs waste rate of this energy that for me up to the axeman skills and the unified sharpness of the blade.
Love the science!!!
And wouldn't handle length play a part in adding velocity?
yeah, for sure. I said at some point that we were assuming a given handle length for discussion, but certainly it plays a role.
SkillCult right. I forgot.i have two boy"s axes, one w/ 28 inch handle and one w/ 26. The shorter one is pretty much unusable as is.
I fuckin love that book.
It's fun.
Is paleotonics or something like that your ebay
Yes, paleotechnics
I didnt even realize that I was in a bidding war on your ebay, I let that axe head get away.
Its not paid for yet, so who knows! If the guy doesn't pay, I'll put it back up. It does have an offcenter eye. That is actually why I put it up, since I have more than I'll probably ever use. Otherwise it looks nice. I'll try to remember to let you know if It goes back up the high bidder was from Germany. Assuming your talking about the plumb and not the DH dh is already shipped.
SkillCult Ya it was the plumb, my ID was tundercat
Your right on faster the better just like a bullet faster it spins the more it stabilizes for accuracy
First, thanks for the well-reasoned discussion!
Second, which McDonalds are you talking about, just in case I'm on my way through your town one day. Buzz kill!!
Third, the equation is m*v = p not m/v = p. I think you have it right on the board, but wrong in the title. Call me pedantic if you must.
Fourth, KE = 1/2mv^2. This is important for you theory that velocity is better than mass. The velocity term is squared, so velocity does have a greater influence on KE. So if you are capable of varying either or both terms (mass and/or velocity), when you vary velocity it will have a greater effect on the KE you can develop in the axe.
In the momentum equation, both terms have the same effect.
In a closed system... say and axe and a target... the momentum of the system is conserved, not destroyed. The momentum after a collision has to add up to the original value (a simplification: sound, vibrations, heat neglected). I think this is one reason (geometry of axe too) why you wouldn't use a boy's axe to try split 3ft diameter madrone, no matter how fast you can bring it down. In splitting bigger wood you want to transfer more momentum to the log and the mass of the log is high, and the block or the ground effectively is fixed, so the momentum is transferred into splitting the wood and making it move sideways. In chopping, the mass of the log may also be high, but it is really much lighter chips that you are trying to make, hence a lighter, faster axe makes sense.
Geek fest indeed!
I think you are correct in the idea that the parameters driving axe selection involve many, many other factors such as the length of time you expect to work for, maneuverability, portability, feel and preference, type of wood, cutting task at hand, etc, etc. This is my justification for owning more than a couple axes and continuing to look for more interesting ones to try.
I am nowhere near as experienced as you, but I think I prefer a slightly heavier axe - just preference. I feel I can get it swinging in a nice accurate arc and the mass helps keep it on-line when I add my snap near the end. I'm looking for a nice 3 pounder right now, to roughly split the difference between my two favorites...
Cool, thanks. That's interesting about the larger mass of a big round having to be basically pushed aside. that is one of the main arguments for not splitting really big rounds in half. You try to split a large round in half, you are not only separating a very large surface of wood, but you are also trying to displace two large masses. If you chip off the edges of the round, you are only pushing a small mass away from the axe and separating a small surface. How a heavier or lighter mass of the same momentum interact with a body that is struck in it's still inertia state is an obvious question. I think and speak here a lot here in terms of a given axe, because that is just how I think. Of course you can do different things with your embodied energy, but the main variable factor in creating momentum is still velocity with a given axe. Also, i think i said, but there is obviously a practical limit to swinging a small axe very fast and at some point it's just annoying and ineffective. Thanks, good stuff!
Funny, I was thinking about the 'upper speed limit' the other day myself. If you just 'air chop' with nothing in your hands, you can only move your arms just only so fast before you top out. There really is a sweet spot for any given cutting task between axe mass, shaft length, and swing speed. But the better you get and the more you practice with any given axe, the better you can adjust the variables on the fly to make up for the weakness of any particular axe on the given task.
I think that if you are between 2 1/2 and 4 (maximum) for chopping you can make it work for most tasks. When you get to the lower limit or the upper limit, the axe becomes more specialized and limited in what it can do. Likewise for handles. I'm not much of an axeman, so this is just a pet theory.
I very much agree with shanking off pieces from the sides of larger rounds. I wish I had RUclips with your channel and Buck'n Billy Ray Smith way way back when I was 18-19 and splitting lots of wood for Grandma! Stupid chopping block and wedges thru the middle of 36"+ Douglas and Grand Fir!! Lifting pieces up to the block - arggggggghhhhhh!
Also, the higher the velocity and the more exaggerated our movements to gain that high velocity, the more we'll start losing accuracy. All you have to do is imagine the most drastic extremes of both and then start scaling back imagining the spectrum to see that there is a range that is going to be useable and require trade offs of some kind in either direction.
Yeah, i remember beating my brains out on some 20 inch green oak rounds with a 12 pound monster maul with a steel handle borrowed from my neighbor until the split in half. Then one day I saw some pros splitting oak rounds on the ground, just popping off slabs and I was like oh, duh! I seriously need to make some vids on splitting rounds. I could save a lot of people a lot of work. Maybe that should be a priority project this fall. So much to do. Better stop handing out here in the comments :). Oh, one thing that cracks me up is guys splitting their huge rounds into quarters so they can lift them onto a splitter instead of using those same blows to slab them off and make firewood.
That's odd, in most martial arts and other physical disciplines such as sports, you are encouraged to use your entire body as 1 in all movements for maximum efficiency and Force.
I just want to let you know that I do think you are probably correct in your Technique and I'm going to try it that way but I just thought that the discrepancy was worth noting. Perhaps you would like to go a little further into detail after giving it some thought on exactly how you want to word it. Thanks.
Yes, I understand, but I think it depends on the goal and the activity. The goal in practical axe work is not maximum power in chopping, but sustainable, efficient work and adequate power. I also didn't mean to imply that we should move minimally and try to stay still, but that there is a certain economy of motion where over-movement is wasted energy. We could also still move much of our bodies, but not necessarily move some parts very much at all, while others clearly have to move more. And of course doing it gets infinitely complicated to think about. We have so many points of movement articulating in an activity like using an axe. In martial arts they talk about things that some fighters have that can't be taught. I think part of that is a physical efficiency that includes what muscles to use when and what to move how much to deliver energy to a point. If you reduced that to a theoretical perfect efficiency, anything additional might inhibit that power by using energy elsewhere, and/or providing tension that prevents ease of movement and speed. All of that is really interesting to think about. I should go watch exactly what I said. I've thought about doing a video along these lines anyway. Especially addressing comments about splitting wood being like boxing and that you should push off the ground. I'm not trying so much to advocate a certain technique. I don't think I'm qualified probably, but just to point out the very common over exagerration and to get people thinking about physical efficiency s a concept and a goal.
+SkillCult for the record I just want to say that I did know what you meant and perhaps you don't need to explain anymore, for me the most helpful tip you gave was just to Focus on accelerating at the end of the swing, may have been in another video though. and yes that is fascinating to think about the most efficient way to possibly do the work and how much each minut deviation would correlate to different levels of energy waste. I suppose the best way to test it is to just continually shave off motion until you find the exaggerations and excesses. to me I noticed that your entire body does move but your actual torso and hips barely flick an inch which is clearly enough so that's how I've been trying it and it's working great so far, using far less energy than throwing my torso at the Target. just trying to add most of my power at the end of the swing like you said although I find a very fine line between throwing and pushing the axe when trying to accelerate at the end.
+SkillCult for the record I just want to say that I did know what you meant and perhaps you don't need to explain anymore, for me the most helpful tip you gave was just to Focus on accelerating at the end of the swing, may have been in another video though. and yes that is fascinating to think about the most efficient way to possibly do the work and how much each minut deviation would correlate to different levels of energy waste. I suppose the best way to test it is to just continually shave off motion until you find the exaggerations and excesses. to me I noticed that your entire body does move but your actual torso and hips barely flick an inch which is clearly enough so that's how I've been trying it and it's working great so far, using far less energy than throwing my torso at the Target. just trying to add most of my power at the end of the swing like you said although I find a very fine line between throwing and pushing the axe when trying to accelerate at the end.
Well, keep in mind that I wasn't really chopping either and my actual stance and technique might vary considerably. I haven't dug in really heavy on the subject yet anywhere, but I will eventually. It will probably be more questions than answers though, as so many things should be. A common psychological mistake as I think I probably said, is to think the axe needs to be pushed through the wood. the real power of an axe comes from acceleration largely via the particular mechanical advantage it has. I'm not sure what it's called, but it's the fact that a small movement at the end of the handle results in a large movement at the head. but, since our arms are extended from our bodies, they can become as extensions of the handle, or could be seen that way. Also, our waist can bend, so in using an axe, we have these multiple pivot points that can all be working to some extent over the full arc of the swing. one thing that I feel taught me a lot was splitting wood with a maul and trying to minimize total movement. Some really good and effective splitters will throw the maul up really high and slam it down with their whole upper body almost. I can't do that, because I'm not 25 lol. What I found is that I could add a formidable snap by building momentum through most of the swing and then sharply rotating at the wrists in the last 1/4 of the stroke or so to create a sudden acceleration. it could never be done without the pre-acceleration and set up of the majority of the swing, but it's that last little bit that slams it home. But, by using the body variously, that pivot point might be more in the elbows, shoulders or waist, in which case the "handle" is effectively longer. Maybe you can see what I mean in this video. ruclips.net/video/MTroXIXQHIY/видео.html At the end of my swings, very little is moving except my wrists. I think that helped me in chopping to deliver power with less overall movement, which for me at least seems more efficient.
+SkillCult haha yeah I watched that last night and that's the video I was referring to I might have got the information from. by the way for lack of a better word you can just use Leverage and I think people will know what you mean.
The quest for the optimum which may well not be the same for me as you.
I try to think more and more in spectrums and compromises, but not always sucessfully.
My thinking used to be very black and white. I have learned to except more grey these days.
It's contrary to our nature, but we're somewhat trainable lol.
This is akin to using critical theory or a de-constructive type of analysis, and it's really overdone. Look, it's a book written a long time ago, by someone who clearly never took a physics class, but they have experience using axes, not just for the joy of using an axe but for everday use. Back then those people used axes and mauls to split wood to heat their homes, for lumber production, etc. The vast experience of the writer overtakes the technical analysis, it doesn't matter.
The writer is trying to make a point but doesn't have the knowledge to extrapolate ***exactly*** what is going on when using an axe to chop. The writer is correct, he just can't explain it on a technical level so that it's objectively correct, if that makes sense. That being said, this is extremely well done. Very good analysis and knowledge here. Thank you for these videos.
Thanks for the thoughful comment. I'm not sure he did understand the actual problem. The reason I made the video is not theory for academic sake, but because if we understand the problem a little bit, we know what not to do and what factors make effective changes in the work. It is not necessary for someone to understand the problem to be an effective axeman, but I do think it helps to teach people to be more effective and understand the difference betweeen using light axes vs. heavy axes and why heavy axes are not always just more effective across the board.
The kinetic energy is .5*MV^2
12:25 this is why I purchased my council tool Boys Axe. It'll be the last time they put onions my double cheese burger!
Another gem at 14:00 nice hahaha
And it's already red.
Maybe the author used CHOPPING instead of SPLITTING? Maybe it would would make more sense if he was talking about splitting firewood with a maul? Or was he definitely speaking in a felling/bucking context?
He was talking about chopping for sure. Thanks for knowing the difference :). Chopping means splitting to most people now, which leaves us no word for chopping.
the wate of the axe is on how heave the axe is. not on how hard you swang it. and on hot strong you are.
Science terms are only right because some "smart person" says they are right... And obviously you have the experience and gumption to know what's right. You, sir are an expert.
There is certainly something to having consistent terminology, but I"m only going for a shallow understanding of the principals. Now, if I were making calculations or studying the minute differences between the use of light and heavy axes etc, then consistent understanding of standard terminology and principals would be critical. But, words are still not things, or phenomena or whatever it is that they are supposed to describe.
I agree with you, I think Steven is an expert, and I think he did a good job of explaining himself.
Different cultural groups have terms and definitions so that we can accurately communicate with each other. Often the scientific or engineering meaning of a word is very much more specific and specialized than the everyday meaning of the same word/spelling. This is important for accurate communication in scientific or engineering context. There is nothing wrong with this and is not meant to make anyone feel dumb - although there are always some jerks in any crowd!
Tanning may mean something different to you than it does to a 17 year old girl, but I know you're not trying to make her feel stupid. Bucking means something different to you than it does to a cowboy, but you're not trying to make him feel dumb either.
I'm not a big fan of the concept of expert generally, though I do use the term occasionally. My wariness of it is part of a philosophy of critical thinking. I think the term is largely used to over elevate people to an unrealistic status, which can compromise inquiry on both sides and leans to authority/subjugant thinking. If you just look at how much experts disagree lol. I might use the term expert for Mor's Kochanski in relation to axes, but I don't defer to him as a default. I just respect him and am very interested in what he has to say. I feel pretty much the same way about every intellectual or craftsman or anyone else that I think has a lot to offer. I'd rather see myself describing what I think about someone's experience level or knowledge etc than just slap a term on them. Expert might just mean that they have accumulated a lot of data, have collected other people's opinions etc. I think It is more and more a marketing tool these days and actually means less and less.
I also have a philosophy of playing loose with language, which is a preference I've increasingly developed to try to see things for what they are instead of what they're called. It now cracks me up when people insist on talking about terminology instead of the concept. Some guy just left a comment on one of my vids criticizing my choice of words (if choice isn't maybe too strong a term lol) but had nothing to say about the content and meaning which could only be missed by an 8 year old. I understand the importance of concensus at times and in certain endeavors, but terms can become like buzzwords or common sayings that people just throw mindlessly into the mix and leave it at that. defining the phenomenon or things first for what they are, and only then looking at the terminology, forces more inquiry. Making up words, or calling things by some name for a similar thing or phenomenon opens more doors and perspectives for looking at it. It's hard to explain, but I'm more and more about it. Language is a prison and should be approached with irreverence :)
I've always liked at the test of ten thousand hours- if you have done something for ten thousand hours, you have mastery. I think that very few people in the modern age can make that claim with axmanship. It's refreshing to see someone able to be down to earth and humble- you see reality instead of the crap we are fed constantly. Just stay true to that when we're forgotten and you're making millions! See you on the flip side hombre.
no, science terms are "right" because the terms have evolved over thousands of years of people thoughtfully finding the most correct and succinct term to accurately describe repeatable and predictable scientific observations.
we don't call it gravity because one dude had an apple fall on his head, we call it gravity because nobody has disproved newton's observations of gravity.
using an axe which is too big for you is like paying for a big truck when you need to move a coffee table. not only does it cost far too much resources just to get the thing moving, but you can never make use of the room it offers.
Good analogy. I find very little use for heavy axes except in splitting saw cut rounds.
Ahah and it's time for lunch ! Such g0od understanding of human nature
E=(m*v^2)/2 - that's all about chopping :)
Also a heavy ax is more effective on a fallen log or splitting than a standing tree. Gravity is your friend.
If you're accurate, and don't tire out. You could make an argument that a lighter axe with greater precision of cuts could be more effective
LOL "are you ready?"..
Regarding the mass slaughtering, I find it ironic that you choose McDonalds. 😁😉
The illustrations look like they need you to color them or paint them with your blood. ;-*
I'll get right on that.
14:05 Haha!
Fix the title. mass x velocity = momentum.
Is it X? I know momentum is a product of mass and velocity, but I didn't know what symbol to use, so I just put a slash. I would have used a dot, but there's not dot on my keyboard.
the "x" denotes multiplication. The "/" used in the title denotes division. So you are correct in your statement that momentum is the product of mass multiplied by velocity but what your title is saying mathematically is that momentum is the quotient of mass divided by velocity which is incorrect. Hope that helps.
Yeah, got it, fixed. Thanks.
• or •
have you ever felt a tree on the moon?
Yeah, but it slapped me.
It's theoractical!
I like it!
or theoraxtical!
HEY NO OBJECTIVE CLUCKING TODAY LOL
OK. I have to go cut a tree now. Thanks
Go mike go!
Geek out with your axe out
nice one ha ha.