Ka Bar Heavy Bowie

[the possum]

James-
Thanks for taking the time to share your thoughts. It's nice to get another perspective. These days about the only knives in that length range I use are kitchen knives; I've pretty much settled on using folders paired with a very large knife instead. So I was wondering if there was just something simple I'd forgotten.

I've really been paying attention to threads that discuss balance these days, and there are some things I'd like to add as well.

A 9" blade should be considerably blade heavy IMO. The longer reach & blade heavy balance make for a more effective chopper. And the added reach helps to compensate for the clumsy-ish feel for self defense applications - there is a fine line there... For example, you need some tip control if you are going to use the point in a SD application - go too blade heavy & you loose some of that...

Having more mass in the blade or saying "blade heavy" is not really the same thing as discussing the balance point though, like you were talking about in post #14. I can agree that you'd lose some tip control if the blade is too heavy for the rest of the package, but the same thing can be said about blades that get too light. The word "balance" implies that too much is just as bad as too little. It usually seems to me that most guys will err on the light side. The guys on swordforum have often pointed out that if the blade is balanced too light, it's easy to overcorrect and get even less control. It reminds me of shotgunners who want to use really short, light barrels to make the gun "quicker".

So I like a balance point just on the blade heavy side of neutral for the ~7" knives - especially for self defense applications: if you go too blade heavy it makes for slower recovery from your swings & makes the knife less suitable for reverse grip applications.

Again, I can agree that a slow knife is a bad thing in a defensive type scenario, but at the same time, the balance point isn't what determines this. You could have two knives of the same length, weight, and balance point that handle totally differently.

Bowie knives in the ~7" blade range can really vary allot:

I still have a hard time calling 7 inch bladed knives "Bowie knives".

For example, the old marine combat knife is slightly handle heavy.... This does translate to fast recovery in self defense though.

I can see this arguement if you're keeping your wrist locked in a convulsive grip. In that case you're moving the blade/hand as a whole. I believe I can see your point about reverse grip as well, but I don't have a lot of experience in that area. But if we start talking about things that involve lots of wrist movement/snapping and blade rotation, then the above may not be true. In fact, the handle heavy knife may actually be slower.

The Ontario SP6 balances ~1/2" in front of the handguard. This is a pretty decent compromise that makes for powerful cuts yet relatively fast recovery. It's pretty well balanced for a blade its size.

It may or may not be well balanced, but it ain't because the balance point is 1/2" in front of the guard, either way. Speed and power don't have to be in opposition to each other. You can have them both at the same time with proper balance. (I used the word balance here to be far more encompassing- taking into consideration your physical strength and the amount of blade presence to accomplish whatever task) My big bowie maneuvers faster than a machete and out chops my 32 oz HI khukri.


All that said, I'm still interested in hearing your thoughts on the matter, especially the parts about reverse grip. I find myself wondering if its just the difference in the way your interacting with the knife, or if "wagging the dog" just isn't as effective in reverse grip....

 

[Cliff Stamp]

I used the word balance here to be far more encompassing- taking into consideration your physical strength and the amount of blade presence to accomplish whatever task....

Most just use it to just mean the center of mass and disregard user strength. For example I always read that the purpose of pommel weights was simply to move the center of mass. The ignorance of personal physical ability I always found amusing because the statements are so definate and never made to be user dependent.

Instead of saying "I am not strong enough to use this effectively for XXX." instead it is said "This knife is too heavy for XXX." and it is usually then either implied or outright stated this is a general design flaw/focus which would apply to everyone as in "This knife makes a poor fighter because it is too blade heavy."

I can't use a 26 oz hammer for framing for any length of time, just have not done it in a long time. My brother can swing one all day, and does so. The exact same hammer, for the exact same task can be balanced too light for him and too heavy for me. Same thing goes for knives, issues of control and redirection of blade depend on the ability to accelerate it.

Acceleration is basically inversely proportional to the inertia which is why people complain about knives being hard to swing if the mass distribution is well away from the point of rotation. However it is also proportional to force and thus someone far stronger will see a blade as much "lighter" with the same inertial resistance because for a given amount of effort he produces far more force and correspondingly more acceleration.

-Cliff

 

[japanesegorilla]

So the basic point being that if something feels good and works well for you; great. It could be the most terribly balanced knife in the world (depending on what your definition of balance is), but it still might be perfect for someone out there.

 

[the possum]

So the basic point being that if something feels good and works well for you; great.

If the above is somebody's stance on the subject, I probably wouldn't try to dissuade them, unless they were being belligerent.

It could be the most terribly balanced knife in the world (depending on what your definition of balance is)...

If there's any basic take home message here, for my part, it's that you should know and appreciate the differences before declaring it the universal ideal. :thumbup:

 

[James Green Dragon]

...Scientists

Yes user strength is relative. However, an overly blade heavy knife is just that. From a self defense perspective, even if you are strong enough to make the more blade heavy knife work for you - bully for you - but you would still be faster with a less blade heavy knife, i.e.; one with "better balance". By that I guess I do mean center of mass - in proportion to length.

Blade length factors into it - but a 7" bladed knife with a balance point 1 full inch in front of the handle is going to feel a tad "over balanced", i.e.; "blade heavy", whether one can arm curl 30lbs or 300lbs. It may be easier to compensate for - but that is still what you are doing - compensating.

So I disagree when Cliff says: Instead of saying "I am not strong enough to use this effectively for XXX." instead it is said "This knife is too heavy for XXX." and it is usually then either implied or outright stated this is a general design flaw/focus which would apply to everyone as in "This knife makes a poor fighter because it is too blade heavy."

Enough with the strawman. A knife that is too blade heavy for its length is not optimal for self defense IMO. Doesn't matter how you spin it, like I said, if you are strong enough to compensate for your knife being overbalanced bully for you - but it doesn't change the fact that you would be more effective with a blade that is lighter & better balanced for that application.

Sure, you can go too light - especially with really large knives or swords but it is very rare with a ~7" knife - I've never picked up a blade that size & thought 'this is too light for it's size' - but I have picked up many knives & thought that they were too heavy to be optimal for carrying and / or too "blade-heavy" to be optimal for self defense with a knife of its size.

Conversely, I agree with Possum when he says: "...The word "balance" implies that too much is just as bad as too little."

Reading between the lines here I think I have stepped on a couple of toes by suggesting that one blade in particular might be more blade heavy than I would prefer for a knife its size. So be it. I stand by my observation even though I would still highly recomend the knife.

Possum goes on to say: "...You could have two knives of the same length, weight, and balance point that handle totally differently." And this is true as well. Handle design, blade shape & design, and overall mass would factor into the equasion too. Did I miss anything?

 

[James Green Dragon]

In reply to the Possum regarding reverse grip: While all blades, even swords can be used in reverse grip, for knives you are really getting in close with such techniques.

Something as simple as going from a palm down reverse grip cut, rolling the arm over to palm up & cutting back the other direction seems a little clumsy & slower with overly blade heavy knives. And I'm not doing this with arm power alone either, getting the feet, hips & trunk into the movement does not change the fact it is faster & feels more controlled with a more neutrally balanced knife. Hooking & passing techniques seem to also feel more smooth & less clumsy with the less blade heavy examples above - something a little handle heavy, like the marine combat knife, just feels better in reverse grip to just about anyone. Subjective? Sure - to a degree.

Possum also wrote: "...But if we start talking about things that involve lots of wrist movement/snapping and blade rotation, then the above may not be true. In fact, the handle heavy knife may actually be slower..."

We are now speaking of a forward grip. And if I am understanding correctly, a snap cut specifically. If so, I agree - your snap cut is faster with a more blade heavy knife. Your recovery, i.e.; ability to translate the cut into another movement on another line may not be faster though...

As for keeping the wrist & arm as a single unit, I do this with the thrust but not with cutting... Heavier & more blade heavy seems to translate to slower thrusts & slower retractions. Least in my book.

And finally, I was very suprised to read that Mr. P's Bowie will out chop his Kukhri knife (!). That is interesting - could it be the result of technique though? Either way, that is different :thumbup:

 

[Cliff Stamp]

...but you would still be faster with a less blade heavy knife

The exact same statement could be applied to any knife which you find "balanced correctly", why don't you switch to one which is easier to accelerate - you have no limits defined, you go so far as to state there are none. In reality this isn't the case, there is a certain amount of weight to slow you down, up until that point you move at maximum speed. If you were much stronger then this point would be higher.

The amount of strength in people varies by about a factor of 5 for adults, someone that is five times stronger than you will "feel" in hand the same thing you feel with a knife that is five times heavier. Thus for them, the knife that you consider to be too heavy could be lighter for them than the knife you consider is optimal for you so how could you possibly argue it is too heavy for them as this would also mean your knife is way too heavy for you.

Different people also have different mechanics, some move very slow (relatively) but have massive strength some also can move much faster but don't have the same strength. You also have to consider the effect of inertial moment and speed on power of the swing, a very low inertial blade would have very low momentum even at high speeds. This is discussed on swordforums on the effect it has on cutting ability in great detail.

Blade length factors into it - but a 7" bladed knife with a balance point 1 full inch in front of the handle is going to feel a tad "over balanced", i.e.; "blade heavy", whether one can arm curl 30lbs or 300lbs. It may be easier to compensate for - but that is still what you are doing - compensating.

How the blade feels when you swing it is not dependent simply on the center of mass, you need to consider the rotational moment. It depends on where the mass is distributed in a nonlinear manner, specifically quadratically with length. You can take that blade and move the center of balance back towards the grip so it is more neutral and make it *slower* in the hand, without changing the length if you greatly increased the inertial moment.

-Cliff

 

[the possum]

...Scientists

I'd prefer to think of myself as a farmer. One who just happens to have passionate interests in several other subjects.

Yes user strength is relative... From a self defense perspective, even if you are strong enough to make the more blade heavy knife work for you - bully for you - but you would still be faster with a less blade heavy knife, i.e.; one with "better balance".

Which knife can you swing faster? A pocketknife with a 1 inch blade, or one with a 2 inch blade? I mean, after all, there's about twice as much blade mass on the 2 inch knife, so does that mean you can swing it twice as fast? Hopefully, you can see that you should really be able to swing both at the same (your maximum) speed, because they're still too light to slow you down. For someone strong, they may find no difference between a 7 and 8 inch knife. I think that's really all Cliff is trying to get at. In high school, the pitcher for our baseball team could throw a fastball at like 75 mph. I couldn't approach that, but I could throw a shot-put farther than him. For his physique, he'd probably be better off with a light & quick knife so he can make use of his natural talent- speed. For my physique, I can use a heavier knife than he could before it would start to slow me down.

I could draw another analogy from medieval archery. A crossbow with several hundred pounds of draw force can't shoot an arrow much any faster than a longbow. They're both limited by the maximum speed that the wood can rebound. But the crossbow could shoot a solid iron bolt that's much heavier than an arrow at the same speed, which is the most effective way to harness its greater power.

Blade length factors into it - but a 7" bladed knife with a balance point 1 full inch in front of the handle is going to feel a tad "over balanced", i.e.; "blade heavy", whether one can arm curl 30lbs or 300lbs. It may be easier to compensate for - but that is still what you are doing - compensating.

You're falling into the trap of thinking that the way a knife feels when just holding it in your hand translates directly to how it will maneuver in quick direction changes and such. This is not true. It's quite possible that the knife with a center of mass 1" ahead of the guard will actually handle faster than one with a CoM at the guard.

Enough with the strawman.

I'll admit that I'm speaking in vague and cryptic terms with all this. I'm testing the waters, to see if you're open to learning a different point of view. I didn't invent the concepts I'm talking about, and they have been discussed at length elsewhere on the web.

Sure, you can go too light - especially with really large knives or swords but it is very rare with a ~7" knife

I am referring more to larger knives, because then the differences are hard to ignore. I think our differing points of view are coming from the differences in the fundamental ways you move a great big knife/sword vs. a small knife.
With a small paring knife for example, you just move your hand/wrist however you like, and the blade obeys without effort. This is not practical with a cut & thrust sword, and it's silly to try moving it in the same way as a paring knife. You have to sorta move around the blade more, making it rotate in various centers. So perhaps our question should be whether you want your fighter to handle more like a paring knife or a sword. In the common range for "bowie knives", I can see that there would be an overlap in preferance depending on what in individual is familiar with. But once you get too big for your own physique and purposes, it's time to switch to sword-like handling. It's silly to try hammering a square peg into a round hole. But I should re-emphasize the the general concepts still hold true regardless of which method you prefer.

Reading between the lines here I think I have stepped on a couple of toes by suggesting that one blade in particular might be more blade heavy than I would prefer for a knife its size. So be it. I stand by my observation even though I would still highly recomend the knife.

No, no sir. You needn't worry about stepping on my toes. I do not own this knife, and I wouldn't bother trying to show you what I consider very valuable information if I didn't think you were a bright & respectable individual. I'm glad you are not afraid to discuss this stuff with conviction. Both of us can learn more that way. :thumbup:

And finally, I was very suprised to read that Mr. P's Bowie will out chop his Kukhri knife (!). That is interesting - could it be the result of technique though?

Possum goes on to say: "...You could have two knives of the same length, weight, and balance point that handle totally differently." And this is true as well. Handle design, blade shape & design, and overall mass would factor into the equation too. Did I miss anything?

Yes. You missed the part where I was talking about balance. Once you have a better understanding of balance, you also understand the behavior I described about my knives.

 

[the possum]

In reply to the Possum regarding reverse grip: While all blades, even swords can be used in reverse grip, for knives you are really getting in close with such techniques.

Something as simple as going from a palm down reverse grip cut, rolling the arm over to palm up & cutting back the other direction seems a little clumsy & slower with overly blade heavy knives. And I'm not doing this with arm power alone either, getting the feet, hips & trunk into the movement does not change the fact it is faster & feels more controlled with a more neutrally balanced knife. Hooking & passing techniques seem to also feel more smooth & less clumsy with the less blade heavy examples above - something a little handle heavy, like the marine combat knife, just feels better in reverse grip to just about anyone. Subjective? Sure - to a degree.

I appreciate your taking the time to reply on this. As mentioned, I do not have a lot of real experience with reverse grip, except perhaps opening feed and seed sacks around the farm, and a few other chores. But just playing around with it, I can certainly see what you mean, especially if I just try moving it the same way I would a small knife (like the paring knife example in my post above).

Possum also wrote: "...But if we start talking about things that involve lots of wrist movement/snapping and blade rotation, then the above may not be true. In fact, the handle heavy knife may actually be slower..."

We are now speaking of a forward grip. And if I am understanding correctly, a snap cut specifically. If so, I agree - your snap cut is faster with a more blade heavy knife. Your recovery, i.e.; ability to translate the cut into another movement on another line may not be faster though...

Yes, I should have specified I was talking about forward grip again. But with the rest, you're kinda losing me. I have a feeling this would be much easier to hash out in person. I'm not sure why you're saying you couldn't recover from a snap cut as easily as you could execute it. Unless you're talking about the different muscles needed to perform each action... With my big bowie, I have swung at a running raccoon, missed, and redirected for a followup swing three times in less than a second. (kept missing 'cause all the brush in my face was blocking my view.) By making the knife's balance work for you, you can swing in one rotational center, make the impact occur in another, recover in a third, and strike again in a fourth, all to your advantage.

When I think of the words "blade heavy", I'm not thinking about whether the balance point lies 1" in front of the guard or 1/2". I'm thinking about the effort needed to do things such as redirect the blade in dynamic situations like above. The two do not necessarily have all that much in common.

 

[Cliff Stamp]

With a small paring knife for example, you just move your hand/wrist however you like, and the blade obeys without effort. This is not practical with a cut & thrust sword, and it's silly to try moving it in the same way as a paring knife.

I like to read more detail here if you get the time.

-Cliff

 

[James Green Dragon]

Alright, the first thing I have to say is :foot:

Y'all make a viable point & I was too obtuse to grasp it. At first anyway. So thanks to Possum & Cliff for taking the time to open a fella's eyes a little :thumbup:

When making an observation about a knife's "balance" in the future I will specify that I mean center of mass & I will also acknowledge that any comments I have regarding how a blade 'feels' are very subjective.

Thanks again to both of you,

James

 

[the possum]

Hey there, James. Been busy the past couple days, but I wanted to let you know there's no reason to feel apologetic for your opinion. It seems to match the prevailing opinion on balance in the knife community at large.

At the same time, I was hoping you wouldn't just drop out of the conversation. With all my cryptic replies, I haven't actually touched on how or why this stuff works the way it does. Yeah, I suppose there will be some subjectivity in anything, but much of what I'm talking about is measurable and quantifiable too.

Right now I'm in the process of modifying the balance on that kukri I mentioned. It handles much faster now. That may be a subjective statement, but I think if you got to hold it you could easily see the difference is night and day. Not really much room for interpretation. When I get it finished, I plan to post here showing how I made it much easier, faster, and less fatigueing to handle, while increasing its chopping versatility, reducing vibration/feedback to the hand, and without sacrificing chopping power. This is all done at the same time with proper balance.


Cliff-
Re: sword/big knife vs. small knife handling-

Let me back peddle a bit here and say maybe I came across a bit strong with my statements in order to make my point. At the time, I was thinking more about dynamic situations where you're trying to move at full speed. While just clearing brush or chopping with my big bowie, I suppose there's not a whole lot of difference in the way I'd use it compared to a smaller knife. I just work at a slower pace.

I was mainly talking about how with a small knife, the moment of inertia is so small that you can basically disregard it. You can accelerate and stop the blade as quickly as your arm. You can wave the knife back and forth with the wrist locked, and just completely stop the motion and reverse it again.

Once you get enough mass out there, even if the blade is well balanced it will lag behind your hand if you try accelerating it with a locked wrist. Instead of fighting this and trying to stop the blade to redirect it, you let your wrist rotate so the blade naturally lags behind, and then snap it around again once your arm is up to speed. Instead of trying to force the knife/sword to rotate around the center of your grip, you use its center of mass and work around the knife. Instead of trying to completely stop and reverse its motion, you use circular movements to simply redirect is existing momentum.

I’ve tried to draw an analogy with a teeter-totter or see-saw at a playground. It’s hard to pick up a big plank of wood by one end and just wave it around. But it’s easy to pick up/move the end of a teeter-totter since you’re not lifting the entire weight of the plank. You’re just rotating it around its center of mass.

This is important, because the closer your hand is to the center of mass, the harder it is to initiate acceleration. When your hand is further from the CoM, you have more leverage on it. Thus a big knife balanced right at the guard or behind it will be difficult to rotate in fluid circular movements- since you are basically gripping the CoM, it will want to move as a whole. Again, think of the teeter-totter example above. Pick up that same big plank of wood in the center, and it will be difficult to spin it around with wrist power.

But again, even if you want to use the big knife like a small one, tapers will still help you.

 

[Cliff Stamp]

When I get it finished, I plan to post here showing how I made it much easier, faster, and less fatigueing to handle, while increasing its chopping versatility, reducing vibration/feedback to the hand, and without sacrificing chopping power. This is all done at the same time with proper balance.

That is the defination of balance for knives that makes the most sense to me considering the meaning of the word. A combination of center of mass, weight and inertial moment which give optimal speed, power and acceleration. The best combination will depends on the physical characteristics of the user and the goal. I doubt a katana, foil, and broadsword are all used identially, thus correct balance for one isn't going to be optimal for the other.

Instead of fighting this and trying to stop the blade to redirect it, you let your wrist rotate so the blade naturally lags behind, and then snap it around again once your arm is up to speed.

This is done with many large working blades, it is a common machete technique, on the backswing the knife is relaxed in hand and the blade falls parallel to the forearm, as the arm is snapped down the blade is jumpstarted by basically the shoulder which can easily handle a pound or so all day long, but this would wear on the wrist fast.

Thus a big knife balanced right at the guard or behind it will be difficult to rotate in fluid circular movements- since you are basically gripping the CoM, it will want to move as a whole.

I think this is an interesting aspect which comes from considering movement vs static in hand. It gets easier to accelerate an object far from the CoM, but this does tend to shift the inertial moment which will reduce the acceration from a given torque so again you need to find a balance of both properties and with tapers and pommel weights you can move the CoM and inertial moment in difference directions to allow the optimal focus. It would be interesting to stick small acceleration meters on the blades and actually measure the velocity and acceleration.

-Cliff

 

[the possum]

I find myself pretty much in agreement with yer thoughts here.

This is done with many large working blades, it is a common machete technique, on the backswing the knife is relaxed in hand and the blade falls parallel to the forearm, as the arm is snapped down the blade is jumpstarted by basically the shoulder which can easily handle a pound or so all day long, but this would wear on the wrist fast.

Yeah, I know. It's one of them simple things that everybody does. But it sounds like some folks just don't stop to think about the difference. And yeah, if I was gonna be chopping for an extened time, I would just work at a slower pace and not use as much rotation. But it works great when you need to move quick. This was the gist of what I was trying to say in that email when I sent you the video of me cutting off that deer's head. (By the way, did you ever get that? I had some trouble getting it to go through at first.)

I think this is an interesting aspect which comes from considering movement vs static in hand. It gets easier to accelerate an object far from the CoM, but this does tend to shift the inertial moment which will reduce the acceration from a given torque so again you need to find a balance of both properties and with tapers and pommel weights you can move the CoM and inertial moment in difference directions to allow the optimal focus. It would be interesting to stick small acceleration meters on the blades and actually measure the velocity and acceleration.
-Cliff

Yep. All things "in balance".

 

[Cliff Stamp]

Yes, email got through fine. In general, aside from doing comparisons and such and benchmarking raw power, I work at a much reduced pace, the amount of fatigue increases exponentially with effort, you can run at 50% for a lot longer than you can at 90%. Looking forward to the khukuri-balance post.

-Cliff

 

[DPris]

Bejabbers! My eyes are starting to cross.
So much esoteric analyzing.
I guess I'm way too simple.
I just go cut stuff when it needs it.