monster maul

[mgapinski]

Sotz Corporation (at one time of Columbia Station, Ohio) made a 15lb "monster maul". Who knows where (if?) they're made now? A new company name? Where can I get one of these? thx!

 

[DiscoInferno]

Sotz Corporation (at one time of Columbia Station, Ohio) made a 15lb "monster maul". Who knows where (if?) they're made now? A new company name? Where can I get one of these? thx!

My local Ace Hardware has a monster maul for $27. I think it was 12lb, and the (metal) handle seemed a little shorter than a regular maul.

 

[computeruser]

Iron & Oak, makers of hydraulic log splitters, also sells a megamaul. Works quite well, though it seems that all the megamauls on the market are 30" rather than the 36" that they should be. Go figure. Anyway, they seem to go for about $35 around these parts and are well worth it.

 

[11 Bravo]

My fellow Michiganders.........Why would you want to swing something that heavy.......Maybe someone out there has the physics skills, but seems that you could get a faster head speed with a 8 or 10 # maul, thus getting a better / more effective strike....Someone out there has to have done the math on this at one point.....

 

[JayY]

Is it kinetic energy or momentum thats more important? Once a 12lb maul is in motion its hard to stop yielding more splits.

Kinetic Energy = Weight(Velocity Squared) /2(Acceleration of Gravity)
Momentum = Weight(Velocity) / Acceleration of Gravity

As you can see, weight plays a major role in the momentum formula. I think its the same reason bowlers don't use 6lb balls.

Jay

 

[DiscoInferno]

My fellow Michiganders.........Why would you want to swing something that heavy.......Maybe someone out there has the physics skills, but seems that you could get a faster head speed with a 8 or 10 # maul, thus getting a better / more effective strike....Someone out there has to have done the math on this at one point.....

I don't actually have one, I split with a 6lb maul in MI and a 4lb "super splitter" (axe with wings) in MD. I just saw it in the store recently and was thinking of getting one to see how it works and feels, but I can't imagine doing the bulk of my splitting with something that heavy.

I think that KE, 0.5*m*v^2, is more important than momentum, because the maul-wood collision is mostly inelastic. The usual claim is that lighter mauls are better because of the squared velocity dependence. This seems to ignore the fact that all of the energy in the maul at impact comes from the user in any case; thus absent better knowledge of the human power curve it's really not clear what the "best" weight is for a given person. With a heavy maul more potential energy is temporarily stored by raising the maul overhead, and this gets added via gravity to the energy actively imparted on the downswing. So one could argue that a heavy maul is able to transmit more energy to the wood by generating more energy in the backswing than a light maul. But then the goal isn't to deliver maximum energy on every blow, it's to deliver just enough to split the round while tiring the operator the least possible. Using a 12lb maul on straight-grained red oak would be massive overkill. Using it on elm might save you a lot of swings with a lighter maul.

 

[Gooserider]

Stotz is out of business :-/ A pity becase their maul was wonderful, I used one back when I was high school age.

Northern sells THIS ONE which looks like a good clone, I have an earlier version that I got from them, and which works quite nicely.

I have both the monster maul clone and an 8lb sledge/maul, and I've tried and use both, but mostly the monster maul which IMHO is less effort and gives a better / more reliable split/hit ratio on reasonable splitting wood.

If the peice IS straight grained, and nice splitting stuff like red oak (most of my wood lately) then I get a fairly reliable split with the 8 lb job, but I find more of my red oak has hidden gnarly bits that don't really show until after the split, and the monster will power through those, while the 8lb doesn't.

In terms of effort, I think the monster maul is easier because most of the hit speed is generated by gravity. As the great prankster Galileo proved by pelting the crowd at the foot of the leaning Pizza tower (of course it leans, they need to make the foundation out of something more solid than mozzarella) gravity will impart the same speed to both tools, though the 8lb maul might go a bit faster because it has a longer handle and is thus following a longer arc.

Thus the Monster will have an advantage in both kinetic energy AND momentum since it weighs more.

However while the monster you mostly just let it fall while you guide it, but don't try to accellerate it that much, you can accelerate the 8lb sledge to a much higher degree by putting some muscle into it, and that will let you get more kinetic energy into the lighter hammer, and bring the momentum into the same range.

But that means I just throw the monster up and let it fall, while the light hammer I have to both throw up AND pull it back down - IMHO much more effort.

I'd rather "overkill" the easy splits and go right through them with the monster, than under estimate the needed force with the little maul and have to hit it multiple times.

If I do have a split that I expect to be easy, I just don't pick the monster up as far...

Gooserider

 

[DiscoInferno]

However while the monster you mostly just let it fall while you guide it, but don't try to accellerate it that much, you can accelerate the 8lb sledge to a much higher degree by putting some muscle into it, and that will let you get more kinetic energy into the lighter hammer, and bring the momentum into the same range.

Not to belabor the point, but while it's true that you will be able to accelerate the lighter maul to a higher velocity, it doesn't necessarily follow that you will be able to put more KE into it than you can into the heavy maul. If you put the same effort (energy) into the downswing for each, you will add the same KE. The only way the lighter maul gets more KE is if the human force-velocity curve favors higher velocities. But some googling indicates that the force-velocity curve of muscles is maximum at rest and decreases as the velocity increases. Since energy is force acting through a distance, this suggests that you can put more energy into the slower, heavier maul than into the faster, lighter one. At least for one swing.

At the extremes this is obvious. Imagine a 1oz maul; you'd never be able to swing it fast enough to make up for its light weight, and thus you wouldn't be able to transfer much energy to it. Now imagine a maul so heavy that you are just barely able to get it up over your head, and then swing it down as hard as possible. Maybe you won't increase the acceleration much over gravity, but because of the squared-dependence on velocity and the large mass it still represents a lot of energy. You've just converted your maximum effort into PE on the backswing and KE on the downswing, and if the log doesn't split then certainly a lighter maul wouldn't have either. As a practical matter, though, the ultra-heavy maul would tire you out so fast that it wouldn't be efficient to use much. So somewhere in the middle is the "sweet spot" for most splitting.

Now I'm going to have to go get a monster maul, just to see if any of this theory holds water...

 

[Gooserider]

However while the monster you mostly just let it fall while you guide it, but don't try to accellerate it that much, you can accelerate the 8lb sledge to a much higher degree by putting some muscle into it, and that will let you get more kinetic energy into the lighter hammer, and bring the momentum into the same range.

Not to belabor the point, but while it's true that you will be able to accelerate the lighter maul to a higher velocity, it doesn't necessarily follow that you will be able to put more KE into it than you can into the heavy maul. If you put the same effort (energy) into the downswing for each, you will add the same KE. The only way the lighter maul gets more KE is if the human force-velocity curve favors higher velocities. But some googling indicates that the force-velocity curve of muscles is maximum at rest and decreases as the velocity increases. Since energy is force acting through a distance, this suggests that you can put more energy into the slower, heavier maul than into the faster, lighter one. At least for one swing

.

Look at the equations, the curves are different between kinetic energy and momentum. Momentum is a product, so the result stays about the same as long as the change is proportional - If I reduce the mass by a third, and increase the velocity by a third, the net momentum remains the same.

OTOH, Kinetic energy goes up as the SQUARE of velocity - I make the same change as above, and end up with MUCH more kinetic energy because the velocity increase is squared, while the mas decrease is only a multiple.

quote]At the extremes this is obvious. Imagine a 1oz maul; you'd never be able to swing it fast enough to make up for its light weight, and thus you wouldn't be able to transfer much energy to it. Now imagine a maul so heavy that you are just barely able to get it up over your head, and then swing it down as hard as possible. Maybe you won't increase the acceleration much over gravity, but because of the squared-dependence on velocity and the large mass it still represents a lot of energy. You've just converted your maximum effort into PE on the backswing and KE on the downswing, and if the log doesn't split then certainly a lighter maul wouldn't have either. As a practical matter, though, the ultra-heavy maul would tire you out so fast that it wouldn't be efficient to use much. So somewhere in the middle is the "sweet spot" for most splitting.[/quote]

I assume that I am accelerating the hammer if my arms are feeling resistance as I make the downswing. If I try to do a "muscle swing" on the monster, I feel resistance all the way down. If I do the muscle swing on the light hammer, I get much higher resistance initially, then decreasing resistance unless I go to extreme effort. This tells me that the monster is being accelerated by my body all the way down, where the light hammer has reached a speed that I can't readily increase, IOW, it has maxed out the velocity I can give it. Note that the acceleration from gravity is slow at first, so I'm maximally accelerating the lite hammer most at the beginning of the stroke when gravity is helping me least. Bottom line is that I can both see and feel that the lite hammer is moving MUCH faster when it hits, but it doesn't do as much when it does.

Now I'm going to have to go get a monster maul, just to see if any of this theory holds water...

IMHO it's a useful tool, I drag it out first when I'm splitting...

I take much of what they say with a HUGE grain of salt, but I remember years back, Mother Earth News did a "split off" comparison test between different splitting technologies, and their editors were unanimous in giving the Monster Maul the award for best manual splitter in terms of most wood split with least effort. They put "sledge and wedge" much further down the list on the effort scale, but found it the most 'reliable' in that you could effectively split just about anything if you hit it enough.

Gooserider

 

[DiscoInferno]

However while the monster you mostly just let it fall while you guide it, but don't try to accellerate it that much, you can accelerate the 8lb sledge to a much higher degree by putting some muscle into it, and that will let you get more kinetic energy into the lighter hammer, and bring the momentum into the same range.

Not to belabor the point, but while it's true that you will be able to accelerate the lighter maul to a higher velocity, it doesn't necessarily follow that you will be able to put more KE into it than you can into the heavy maul. If you put the same effort (energy) into the downswing for each, you will add the same KE. The only way the lighter maul gets more KE is if the human force-velocity curve favors higher velocities. But some googling indicates that the force-velocity curve of muscles is maximum at rest and decreases as the velocity increases. Since energy is force acting through a distance, this suggests that you can put more energy into the slower, heavier maul than into the faster, lighter one. At least for one swing

.

Look at the equations, the curves are different between kinetic energy and momentum. Momentum is a product, so the result stays about the same as long as the change is proportional - If I reduce the mass by a third, and increase the velocity by a third, the net momentum remains the same.

OTOH, Kinetic energy goes up as the SQUARE of velocity - I make the same change as above, and end up with MUCH more kinetic energy because the velocity increase is squared, while the mas decrease is only a multiple.

I'm not ignoring the squared dependence of energy on velocity; I'm invoking it. (I'm ignoring momentum altogether, because it's not clear to me that it's relevant.) You seem to be making the common assumption that the human mass-velocity tradeoff curve between mauls is linear; that if I reduce the weight of the maul by 1/3 I will be able to move it 1/3 faster, conserving momentum but actually increasing KE. But I don't think that's the case, for the very reason that it suggests that I did more work (energy) swinging the light maul down than the heavy one (contradicting both of our experiences). I think it's probably closer to correct to say that reducing the mass of the maul by 1/3 (to 2/3 of original) increases the velocity I can swing it to sqrt(3/2) of original, thus conserving energy delivered. The squared velocity dependence cuts both ways - it provides "extra" KE at impact but it also means that it's "extra" hard to get a heavier maul up to speed.

A different equation for energy (work) is W=F*d, force times distance. If we assume we exert a constant force throughout the same length downswing, then we apparently did the same work with any weight maul, imparting the same KE at impact. But the force-velocity curves I mentioned before actually show that muscle force decreases as velocity increases, so we can actually exert more force (and thus impart greater KE) on the heavier, slower maul throughout the downswing. So I think this matches your experience. I think we agree more than disagree.

Enough boring physics! Off to split wood...

 

[Gooserider]

Well, I may be able to get more definitive answers soon - The GF's parents are both Oxford physics Ph.D.'s and retired professors, and the chair of the Mass LP, and Presidential Candidate George Phillies is a Ph.D. and proffessor at WPI. I've posed the question to all three, will see what the experts say...

That said, my impression is that the lighter maul is moving faster when I hit with it, I don't know if it is a 3rd faster (to keep momentum constant) but it certainly is fast enough to have a higher kinetic energy. However it doesn't seem to have the same momentum...

I guess the parrallel question is which will do more damage to a structure - a VW Bug at 60MPH, or an 18 wheeler at 30MPH? Given the square function of velocity, I suspect the Bug would have higher kinetic energy, but it just makes a splat - the truck has the momentum advantage, and takes down the structure....

I think momentum is the more important factor, because it represents inertia - the tendency of the maul head to keep on moving... The thing that splits the wood isn't just the impact, but rather the penetration of the head into the wood which transfers the downforce of the head into the right angled spreading force that separates the wood fibers. The light hammer tends to stop when it hits the surface, transferring it's energy randomly into the round where it dissipates. The slower, but higher momentum Monster tends to penetrate deeper because it just doesn't want to stop, and thus transfers more of it's momentum into the spreading force of the wedge shaped head.

At any rate, I agree the discussion is mostly theoretical - the best tool a person can use is the one that he feels does the best job for him, regardless of the physics involved.

Gooserider

 

[DiscoInferno]

Well, I may be able to get more definitive answers soon - The GF's parents are both Oxford physics Ph.D.'s and retired professors, and the chair of the Mass LP, and Presidential Candidate George Phillies is a Ph.D. and proffessor at WPI. I've posed the question to all three, will see what the experts say...

From experience, I say expect 3 different answers...

That said, my impression is that the lighter maul is moving faster when I hit with it, I don't know if it is a 3rd faster (to keep momentum constant) but it certainly is fast enough to have a higher kinetic energy. However it doesn't seem to have the same momentum...

It needs to be about 22.5% faster to match the KE.

I guess the parrallel question is which will do more damage to a structure - a VW Bug at 60MPH, or an 18 wheeler at 30MPH? Given the square function of velocity, I suspect the Bug would have higher kinetic energy, but it just makes a splat - the truck has the momentum advantage, and takes down the structure....

If the semi weighs more than 4 times the bug, then it has more KE. My guess is that even unloaded it does.

I think momentum is the more important factor, because it represents inertia - the tendency of the maul head to keep on moving... The thing that splits the wood isn't just the impact, but rather the penetration of the head into the wood which transfers the downforce of the head into the right angled spreading force that separates the wood fibers. The light hammer tends to stop when it hits the surface, transferring it's energy randomly into the round where it dissipates. The slower, but higher momentum Monster tends to penetrate deeper because it just doesn't want to stop, and thus transfers more of it's momentum into the spreading force of the wedge shaped head.

You may be right about this. A lot of KE is wasted in various ways, such as friction. It could be that momentum is the better predictor of splitting power than KE.

 

[Gooserider]

Well, I got one response - This was from George Phillies, and I'm not sure I follow it - partly because he doesn't seem consistent in his variable case, so it's a bit confusing, but I thought the relevant part about "drop it and let the weight do the work was important - if using that approach, the 12lb head will definitely hit harder.

k = P^2 /2M
K = KINETIC
P= MOMENTUM
M= MASS

The HEAD WITH MORE k ALSO HAS MORE p.

Try THE EXPERIMENT.

Also, there are issues with overloading the back with swinging heavy objects.

However, these are moderately different in moment of inertia.

I shall repeat the lesson from the professional construction worker, dealing with a sledge hammer. You get it up there and drop it. You don't really push it much; it's weight should do the work. This protects your joints for old age.

The moments of inertia MR^2 differ by a factor of two.

My "swing" method basically involves "shooting" the head almost straight up, then letting it drop forward - I find the effort needed to throw 12lbs up isn't significantly greater than the effort needed for 8lbs, but I don't work as hard on the downswing with the heavy head.

Gooserider