Heavy Slow Loader

 

The very first intentional detachment made with the wooden club.

As you can imagine, with such a small core, and trying to use an indirect support scenario, I had to fly through the swing at nearly the speed of light, in order to make the detachment without knocking the little core out of my hand. But, thank God for wood, even with a two pound weight, it will not shatter the stone. What a relief. Also, this is one of the things which makes flaking go so fast - it is fast. Also, if you do this for two days straight, your arm will probably be near to falling off.

Very first set of detachments with wooden club

One of first detachments with wooden club

One of first flakes detached with wooden club

Small core

 

small untrimmed core

 

small core

 

Small wood club core ready to be further reduced by hammerstone

 

small core

 

Blade from side

 

Blade from back

 

Blade from front

 

 

 

 

 

Wooden club cortex removal

 

Wooden club cortex removal

 

Beautiful unknown Yucatan chert

 

 

Thick lipped screw up flake

 

Interesting screw up flake

 

 

 

 

 

 

 

 

 

Razor thin flake

 

Side of razor thin flake

 

Razor thin flake

 

Small two pound club

Retooling small two pound club with abrader

Upper left - two piles of flakes - wood (l) and stone (r)

 

Pillow bouncing pad

 

One inch thick flake side

 

One inch thick flake back

 

One inch flake thick front

 

Flake V

 

Flake W back

 

Flake W front

 

Flake W Side

 

Flake X back

Flake X side

 

Flake X front

 

Flake W back

 

Flake W side

 

Flake W front

 

Flake X back

 

Flake X back

 

Flake X side

 

Flake X front

 

Flake Y side

 

Flake Y front

 

Flake Y back

 

Flake Z side

 

Flake Z front

 

Semi translucent Yucatan rock candy chert

 

Wooden Billet knapping and Core/Blade creation

When I first tried to use the wooden billet it seemed abolutely impossible, and I was quite disappointed. Fortunately, I did not throw the billet away - although I came close. After a few days of hit and miss trying, I realized that everything I knew about hammerstone usage was NO LONGER APPLICABLE. So, don't give up when you first try. At the end of these photos, I will explain the concept of creating conditions where two forces are driven in the exact opposite direction of each other (instead of into each other), and why a soft compressible billet can actually generate more force without shattering the stone, under certain situations. In an indirect support scenario (which I will also explain) this is imperative, in creating high pressure like slow loading forces which travel through a portion of the stone, and cause detachment, before the core can move due to intertial support (which I will also explain). These photos reflect the first steps in a new direction. They are the equivalent of the first time a person tries to pressure flake.

Small to mid sized wooden billet (8) lbs. - I am now ready for a much heavier one (20 lbs?), and for a partner to hold the core. (Big blade production)

Untrimmed small conical core left over from wooden billet knapping - ready for hammerstone reduction

These type of flakes are very easy to make, very rapidly, and in different sizes, with a conical core and a wooden billet

Small core - notice how I am working off of near ninety degree rims

Thick lip which terminated abruptly.

Retooling the frayed wood with "fire and grinding"

Blows to the gindstone reduce the charred surface. The surface should not be overly charred, nor overly frayed.

Original condition with minimal use

Larger stone core.

Large flake created with the wooden billet.

Another small core photo.

DISCLAIMER NO. 1:

If you are inspired by what you learn here to want to experiment with easily creating large Clovis, or Solutrean, cores and blades, in a previously unknown way, I want to help you avoid a great pitfall. The tool itself, a heavy wooden billet, cannot achieve these results until (a) the knapper understands how to direct the force of his support (not just the force of the blow), diametrically opposite of the force of the blow (b) the knapper devises ways to "hold" the core so that the blow does not pull away the core, with the resultant flake. In this case, the force exerted by the support, and the force exerted by the blow, should move away from one another and not towards each another. If the knapper simply sets the core upon the ground, and strikes down upon the core's rim, with a wooden billet, he his going to be met with a very disappointing "boing, boing, boing" as the resilient wooden billet bounces repeatedly off of the core. (At this point, many knappers would quickly be tempted to curse the billet and throw it in the trash.) The trick is to figure out how to cause the two forces to pull away from the core, when the blow is delivered - not collide with each other, head on.

The purpose of using wood is so that one can deliver an incredibly powerful heavy blow, in the opposite direction exerted by the force of the support, by utilizing the billet's heavy weight. But, due to the billets unusual softness, the incredibly powerful blow will not shatter the core being struck. Instead, you will produce two very powerful forces moving away from each other, which in essence, pulls the core apart.

Unfortunately, virtually all flake mechanic models, and knapping illustrations, depict a 2-object model of the animate object (the hammerstone) doing the striking, and the inanimate object (the core) being struck, while omitting the third object, which exerts force - the SUPPORT. Also, what is overlooked is the fact that the support, beyond immobilizing the piece, exerts force in one of two directions, depending on whether the knapper has employing a direct support system, or an indirect support system. Each support system works in the opposite manner, as well as in the opposite direction.

The direct support system exerts force head on, in direct opposition to the blow of the billet, or hammerstone. In this scenario, the two forces collide head on, and the core is "compressed" in the very center. The indirect support system exerts force in the diametrically opposite direction, as the force of the blow pulls away from the core. In this scenario, the two forces "decompress", or pull the core apart as the force of the blow energetically "peels off" a flake.

The problem with the direct support scenario, in core blade production, is that the core resting upon a direct support (say, the ground), produces a singular upward force, which is exerted against the downward force of the blow. For example, when one block of stone is placed upon another, the entire unit is just as resistant to downwards force as if the two blocks are fused together. In the same way, a core that is placed upon the ground, and struck with a downwards blow, exerts an unseen upwards force, due to the mass of the ground below.

This is why it is so relatively difficult to detach flakes when the core is sitting upon the ground, and is struck with downward blows (except in the event that you overpower the inherent strength of the core, by the greater inherent strength of the hammerstone - which also produces a shattering effect).

The reason that most knappers never realize why the direcections of these two forces are so critical, is because they learn by experience that so long as the hammerstone is stronger than the core, they are able to "smash off" a flake, by "plowing" through the slightly weaker core, in a direct support scenario. What they do not realize is that the difficulty is greatly increased because they are actually causing two forces to collide head on, within the core itself, instead of "pulling flakes off" - by directing the forces apart from each other - which works far better if one wants to replicate what some call "blade and core technology". Also, this is why, in the direct support scenario, it is easier to shatter the core, to some degree, while not even detaching a flake. If, in the event that the hammerstone contains some inherent weakness, the hammerstone will give way to the stength of the core (plus the ground), and crack apart.

Unfortunately, in blade and core production, while using direct support, the knapper views the highly limited flake detachment as being a "success", and assumes that if he can get "better" he will produce better blades. Thus, what he views as "success", blinds him to the fact that he is creating, instead of resolving, a fundamental problem, which cannot be visually seen. This is the problem of two forces colliding against one another, in the core, instead of pulling away from each other. This problem becomes fully revealed the first time he deliberately attempts to use a billet, such as a resiliant wooden billet, which is obviously softer than the the core being struck. Under previous conditions, the relatively "soft nature" of the core gave way to the hardness of the hammerstone, as the two forces collided head on. With the new wooden billet, which is obviously not as hard as the stone core, the problem is drastically increased, because not only is the downward force, exerted by the blow, incapable of exerting a force greater than the upward force of the ground, but even the soft nature of the billet, cannot "plow" through the stone core. And, the dissappointed knapper's blows simply result in "boing, boing, boing", as the unseen upward force, exerted by the ground, through the core, repels the blows of his wooden billet.

At this point, the knapper will take one of two routes. Either, he will abandon the heavy wooden billet, as though it were a miserable failure, or he will realize that has finally been backed into a theoretical corner, which he must resolve, however hard it may appear. You can imagine where most knappers, who only think in terms of direct support, end up. This is why Solutrean, and Clovis blade production is more common in textbooks, than among modern knappers. This is also why in many knapping texts, the issue of the force, exerted by the support goes unrecognized. In fact, many illustrations omit the force altogether, as though the core, or object being struck is floating in space.

In resolving the problem, the knapper will eventually be forced to come to grips with the issue of the force exerted by the support, and which direction that force is directed, in relation to the force exerted by the blow.

Here is a simple illustration which will partially help illustrate these principles. A person decides that he wants to detach a stalactite, and a stalagmite from a cave. The stalactite, and the stalagmite, are both the same thickness, and the same strength. The person grasps the stalactite, and pulls downwards, from the ceiling. It quickly detaches from the roof. Then, the person grasps a stalagmite, and pushes downward. He pushes with all his strength, but nothing happens. He uses much greater force, yet nothing happens. Why? Because, in the first scenario, the person was pulling away from the support. When he pulled away from the support, the cave ceiling "pulled", or exerted unseen force upwards in the opposite direction (otherwise the roof would have fallen down). The person only needs to use as much downward force as necessary to detach the stalactite, as the two forces moved away from one another, in opposite directions.

In the second scenario, the person is now pushing downwards into the support, while the support (the ground) plus the core, exerts an equally resistive upwards force. These two forces are now being exerted against each other head on. The truth is, the person will never be able to exert more downward force, than the degree of upwards force being exerted by the ground. And, his hands will always be softer than the material the stalagmite is composed of. If any type of break were to happen at all, it would be a crushing break, not like the clean break made when he pulled the stalactite down from the ceiling, where the two opposite forces resulted in pulling the stone apart.

The whole question is this: Is using resistance producing direct support the only way for a knapper to work? No, and not only is it not the only way, but in core and blade production, it is the worse way. The reason that it first appears to be the most logical route to follow, is because the knapper never undertsood that he needed to take the direction of the force, exerted by the support, into account. In fact, he probably never even realized that the support exerts a force. While the knapper was easily able to think in terms of the seen, the objects, and the motions, he failed to think in terms of the unseen, the forces involved. The knapper recognized the force of the blow, due to the visible motion of the hammerstone, or billet. What he failed to recognize was the force of resistance. In knapping, motion always implies force, but force does not always imply motion. The failure to understand that by creating either a direct support system, or an indirect support, which in turn directs the force, exerted by the support, toward the force of the blow, or in the diametrically opposite direction of the force of the blow, prevents knappers from being able to achieve a number of things which are exactly quite possible. This is why if you ask most knappers which way they are directing the force, exerted by the support, in relation to the force being exerted by the blow of the hammerstone, they will have no idea as to what you are talking about. They are still thinking in terms of the seen.

Is there another way to achieve "peeling" large flakes off of a core, instead of trying to smash them off? Sure, turn the equation inside out, and pull the core apart, by causing the forces to move away from each other, while the core is in the center, by pulling the core in one direction, and "pulling" or "shooting" the portion to be detached, in the opposite direction, with two extremely powerful forces. You will soon learn that the sky is the limit - or at least two knappers working together with a huge soft (non-shattering) billet, in rapidly peeling off incredibly large flakes, at a brisk rate of speed, without any crushing - is the limit. (Sorry, you probably refer to these kinds of flakes as "blades". In this form of knapping, they are typical flakes.)

It does not take any special education to understand all of this. The early knappers understood it quite well (without formal education) as is evidenced by the way they were able to "peel" large flakes off of cores. The key is in understanding that there are some forces at work which cannot be visibly recognized because no visible act of motion is involved. These forces result in the form of resistance. In the direct support model, the force exerted by the support resists the push of the force of the hammerstone. In the indirect support model, the force exerted by the support resists the pull produced by the force of the hammerstone. Even though these principles are largely ignored, they are a very relevant part of the equation, in many knapping situations, especially core and blade production. This is the inherent problem with a two object, single force model - it leaves out the force exerted by the support which can be engineered in one of two directions.

All of the flake photos seen towards the end of this page, with the possible exception of some instances in one core photo, were made utilizing indirect support, while the two forces were aimed away from one another, instead of colliding into each other, as is the case with direct support.

DISCLAIMER No. 2:

The various photos found on this page are unique in the sense that they do not reflect the "high art" of flaking with a wooden billet. Rather, they reflect the initial two week learning process of someone who had virtually no prior knowledge, or experience, in the matter.

When I first had the wooden billet made, my hope was that I would be able to use it for thinning larger pieces. The first time I tried to use it, I held a sharp preform in my left hand, and struck it with the wooden billet. The wood caught the sharp edge of the preform, and nearly ripped it out of my hand. I felt quite disappointed. So, I thought to myself that I would at least be able to "knock off" some flakes from a larger chert cobble. I grabbed a chert cobble, a little larger than a grapefuit, and struck it with the wooden billet, just as I would have done with a hammerstone. The blow of the billet violently knocked the cobble out of my hand, as though it were struck with a sledgehammer. While pain began to throb in my fingers, I stared at the cobble laying on the ground, and thought to myself that the whole thing was an idiotic idea. I had heard that a few other knappers used wood billets, but I figured my problem must be with the type of wood I was using. I decided to keep the billet in my car for protection against any mean dogs I might encounter in the Yucatan, which are fairly rare.

A few days later, after laying the billet aside, I decided to give it another try. I found another elongated cobble with one edge that angled back about thirty degrees. As I struck on the cobble, in the way I would have struck it with a hammerstone, there was only a dismal thud, thud, thud. After adjusting the angle of my blow, the strike suddenly resulted in a shrill crack. Faster than my eyes could track, a flurry of "small" flakes had shot away from the stone, and penetrated my leg. I was bleeding. I wondered to myself what made the difference? Was it the "abnormal" angle? Of course, at that time, I was still only able to think, and reckon things, in terms of hammerstone usage.

The photos found here are a very small sample of the first two weeks of learning how to flake with a wooden billet. Eventually, I discovered that the billet (as I am currently using it) can not work on an obtuse angle, and it can not work on a thin edge. But, in edges slightly less than 90 degrees, the billet can be used to produce a driving force which will "pull" long flat flakes from the core, under the right conditions. Eventually, I was forced to learn how to properly trim the core, in order to produce large flakes. This lead to the "discovery" of how to narrow the base of the core, so the flakes will run the full length, and not produce step fractures. Ultimately, what everyone refers to as "core blade technology", I refer to as "optimal set up for heavy wooden billet usage to produce nice large flakes".

As for the cores, I have found that the larger cores work better, due to inertial support. It could also be quite helpful to work with a helper, who can hold the core for you, while you strike it, if the core is very heavy. Once the core gets down to the size of a grapefruit, I just finish it off with hammerstones. By that point, they are in a perfect form for final hammerstone reduction. Also, I try to use a conical core form so that I can angle the force of the blow, away from the core, as the core "pulls" in the opposite direction. The "pull" of the core is not in the form of motion. It is a force exerted in the opposite direction of the blow, in the form of resistance to a change in motion. As Newton would say, for every action, there is an equal and opposite reaction. If a bug and a windsheild collide, to forces hit head on as the two objects "hit" each other. If a person pulls a bug off of a windshield, two forces "pull" away from each other, in opposite directions, as the bug is removed. By employing inertial support, and forming certain core types, such as cones, I am creating a scenario where, for a very brief moment, I can generate a huge "pull" in two opposite directions, as the flake pulls away in one direction, and the core pulls in the opposite direction. By speeding up the blow, I can generate a force which "jerks" the flake off. Of course, once the core becomes smaller, it gets more "squirrely", and moves more easily, and quickly, due to lesser mass. This is not the case with the more massive cores. Here is another way to look at it. Suppose two objects are stuck together, by magnets. And a person pulls on one of the objects with a slow gentle pull. Instead of separating, the second object is simply drug along, even though it may be of greater mass. But, if the person pulls on the object and instead of using a gentle pull, he jerks the first object real hard, and fast, the two objects will separate. Obviously, the greater the mass of the second object, the more easily the separation can be achieved. And, the less the mass, the more difficult the separation will be to achieve. For example, if a person connects a piece of tape to an envelope, and gently pulls, the envelope will be drug along. But, if one connects a piece of tape to a refrigerator, and pulls, there will be a separation. On the other hand, if a person connects the tape to an envelope, and jerks real hard, and fast, it too will separate. Does the envelope have the same mass as the refrigerator? No. But, even though the mass is lesser, it is still so great that it could not begin to move fast enough, in relation to the jerk of the tape. So, separation was instantly achieved. By speeding up the "pull" on the flake, with a faster, weightier blow, the force generated causes the flake to be "pulled off" faster than the core is able to move. In like manner, I create two pulls in the opposite directions at the same time. One pull is created by the wooden club, as the blow generates force away from core. The second "pull", which is reactive in nature, is the opposite "pull", generated by the core, as it resists a change in motion. Because of this, I have to achieve detachment before the core has time to move very much, which is why using more massive cores, makes the job more easy. (One may read this and assume that the core is not being held. This is not the case. The blow from the club is so weighty and powerful that it is going to pull the core, no matter what, in an indirect support scenario. But, due to the core's mass, it cannot start moving fast enough, regardless of the pull, created by the blow, which pulls the flake away from the core. Thus, the split is achieved.) Also, with more massive cores, one can generate greater forces, and produce greater flakes. To illustrate how mass affects a change in motion, think of the difference between striking a ping pong ball, with a ping pong paddle, and striking a bowling ball with a ping pong paddle. Obviously, one of the balls is more resistant to a change in motion. The same would be true if a person were to pull on each ball. Similarly, when a blow causes a plate-like portion of the core to suddenly pull away from the core, the massive core naturally resists the pull, by "pulling" in the opposite direction. It is during this brief frame of time, under these conditions, that the core is "jerked" apart, via the aid of the massive blow, from the wooden club. And, just as was explained in the first "jerking" illustration, involving magnets, the plate like portion must be made to pull away much faster than the massive core can possibly move. This is why cones, and rims, can become so useful - not to mention a helper who might prove to be more helpful than any tool. Speaking of tools, in this case, from my perspective, the mass of the core is just as much of a tool as the wooden club. But, I think if I were to tell people that I was going to use the mass of the core to generate really great flakes, they would not know what I was talking about. Nevertheless, it get's really exciting when you see the mass of a big nodule, and you start thinking about how to use that mass to create great flakes - not that I want to overlook my trusty wooden club. But, in principle, they both are functioning simultaneously, in their own ways, to create the flakes. So, it is hard for me not to see both as tools.

"For every action, there is an equal and opposite reaction."

What does this mean in terms of knapping? Well, let' say a person is pressure flaking, and he holds the biface in his hand and positions his hand against awall. Then, he proceeds to apply direct force with his copper tipped punch, tothe edge of the biface. Aside from all the intricacies of flake mechanics, what are the two primary forces at work? First, there is the active force of the pressure being applied by the knapper's punch. Second there is the reactive force of the wall, and the hand, and the biface, pressing back against the tip of the punch. It is a two way street, not a one way street. Otherwise, if the wall, and the hand, and the biface, did not press back, all three would fly away the moment he tried to apply pressure with the punch. Fortunately for us, theuniverse is not designed to work that way. Now, I am going to skip all the intricacies of flake formation to get to a more fundamental point. That is, in the previous scenario, two forces are "pushing"against each other, practically head on. This is a far more simple fundamentalpoint, then the complex intricacies of flake formation.But, is this the only way to create flakes? Is colliding two forces head on the only way to detach a flake? What would happen if instead of colliding the two forces head on, two forces were made to pull apart in exact opposite directions?Is it possible? Can it be done? How?Well, here is one way. Create a flat topped conical core, and tip it on it's side. Hold the core side ways, from above, while striking down on the nipple rim at 6:00 (lowest point). Now, the force of the blow is going downwards,while the core is being "pulled" upwards. Since the core is relatively large,you don't have to literally pull, at all. The core will "pull" by resisting the change in downward motion (inertial support). The active force you are generating from the blow, can be routed through the flake-to-be more quickly than the massive core has time to move. Even if the core does move some, don'tworry, it will happen after your flake rapidly detaches, due to the hard fast blow.Also, use a really massive object to strike the rim. But, Ben, if I use amassive hammerstone won't I smash through my rim, and shatter my core. Exactly,good thinking. But, where did God write, "thou shalt only use incompressible hammerstones when knapping". You are going to be working with a smoother pressurized force - not quite as shocking - to create two huge forces that pull apart. You are going to be sending two massive forces away from each other,from the core, to create big flakes, or core separations. You are not going to be smashing off little flakes with bulbs. I forgot to tell everyone. You willneed to use gloves when doing this. The vibrations from the incredibly heavy blows, which come through both the wooden club's handle, and the core, are very painful to bare hands. Also, if you are having trouble detaching flakes at first, but feel like the set up is correct, you may need to ramp up the force ofthe blow much harder then you are used to with a hammerstone. Hammerstones cansmash through things relatively easily, because they do not theoretically compress. In this case, you cannot smash through hardly anything with a wooden club Instead, the pressurized force generated by the wooden club, when it is offset by opposite force created by the inertial mass of the core, must increasepass the point of the core's tolerance, or ability to stay intact. This is what causes the split.It's not that hard folks - just different.

Nipple Rim Preparation

It has occurred to me that I have not provided sufficient information, conncerning preparing the rim of a conical core, prior to flake detachment. The rim edge of the top of the core, which will become the striking point, once the core is flipped forward horizontally, should be either perfectly flat, or even slightly depressed. If the core has a hump on top, on the striking point, then when it is struck with the wooden club, the wood cannot "seat" into the surface, due to the protruding hump. For full contact, the end of the wooden club needs to "seat" into the striking point, on the top of the core, on the rim. This "seating" happens when the wood compresses. This allows for fuller contact between the wood, and the stone. Also, it can be quite helpful to abrade the striking point, the point on the rim that will be struck, with a side to side motion. This will help the wood get better "traction", on impact. The sides walls of the core should be straight. There should be no overhang, or indentation, just under the rim. If so, the rim could crack off. The straight even sidewall acts as a sort of support. The angle between the top, and the side should be just less than ninety degrees, for full length flake detachments. The bottom of the core, should be slightly narrowed with hammerstones. If the bottom portion of the sidewall is too thick,the detachment will result in a step fracture, since the flake cannot run full length. I have a picture of this on the website. It was a screwup core, because I did not know this at first. In order to make the top, the sides, and the bottom, suitable for long blade detachment, the best thing is to use a few small hammerstones, and form the core, first. This is easy to do by "popping the cap" off an oblong nodule. This will produce a flat top. Then, in some cases the wooden billet can be used directly on the edge, to flake off the cortex material. This will leave relatively flat sides. But, the bottom may still be too thick. So, flip the core upside down, use hammerstones, and look for ways to flake off end portions, off the sides of the nodule. This will narrow the tip enough to prevent step fractures. Flip the core rightside up, and use the hammerstones to prepare nipple-rim points on the edge. For lack of a better word, the nipple-rim striking point, is a slight protrusion from the edge, when looking down from above. Slight rasping blows of the hammerstone can be used to wear down the edges on each side of the protusion. The top can be abraded from side to side, to reduce slickness - especially on higher grade cherts. Then, the core is ready to be flipped forward and struck,with the wooden billet, with a lightening fast downward blow, right on the nipple like protrusion. Under the right conditions (billetweight, forceful high speed blow, indirect support hold), flat flakes which run the length of the core should rapidly detach. Also, the core should be held from above, not set upon the ground. You may need a helper, in order to do this. Once the core becomes too small, you may find that it is too "squirrely" to control. That is okay. Finish it off with a few hammerstone blows, and start on another large nodule.

Until now, I had not been able to distinguish between impact strength, and density, when using wood. Impact strength refers to the wood's resistance to a blow. This is manifested in the difficulty in denting the wood, as well it's apparent hardness. Density refers to the denseness of the wood, which correlates to the wood's mass, and weight, in relationship to size. A denser wood will be heavier, in spite of it's lesser size, in comparison to other woods. And, a wood with a specific gravity greater than one cannot float.

But, a dense wood is not always a hard wood. And, a hard wood is not always a dense wood. These properties relate to the cellular nature of the different types of wood. Some types of woods, like my chichen club, while being extremely dense, and heavy, may also be relatively soft, and dentable. These types of woods would probably be suitable for "pulling" flakes off of cores, via indirect support. Clubs of this nature may be quite useful in reducing conical cores into blades.

Other types of woods, such as osage orange, may not be unusually dense, but may have a very high impact strength. These types of woods would probably work better for direct percussion, in a direct support scenario. Or, as Craig has shown, for indirect percussion.

Another type of wood, such as ironwood, is both extremely hard, and extremely dense. This type of wood may have an almost rock like affect, in comparison to the other types of wood. This type of wood may be quite suitable for small percussion batons, which are used to strike ground striking platforms. This type of baton could take advantage of both mass, and hardness, simultaneously.

Online notes concerning wood relating to impact strength, density, and specific gravity

An interesting fact about most 'ironwood' woods is that they are sodense that their specific gravities exceed 1.0, so they will sink instead of float when put in water. Examples of ironwoods that can be found in North America include American hornbeam, mesquite, desert ironwood, and leadwood. Leadwood(Krugiodendron ferreum) has a specific gravity of up to 1.42, makingit the heaviest in the United States. The heaviest wood in the world is black ironwood (Olea laurifolia)also known as South Afri, which can be found in the West Indes. It has a specific gravity of 1.49 and can weigh up to 93 pounds per foot.(Osage Orange has a specific gravity of .8)http://everything2.org/index.pl?node=Ironwood

Here is more wood information from a martial arts site:

For example, American Black Walnut in general doesn't have suitable shock strength or dent resistance for this application and we would be tempted to unequevically extend this judgement to all BlackWalnut. Under some (rare) conditions however, an individual tree may produce lumber that will produce a servicable and perhaps an excellent practice weapon. Several of the true hickories from a specific region (which will be discussed later) yield excellent quality lumber in general but an individual piece may be weaker than unusually good piece of material from an "inferior" species.

Impact Strength

Whereas the quality of wood can be described from many perspectives, one of the primary concerns here is its safety and strength during contact which typically occurs with sudden impact. The followingchart, Impact Strength of Materials, shows the strength of various materials when subjected to impact shock (with other wood) expected during paired practice. The test uses a simple spring loaded ram* to test samples of identical size. The sole purpose of the test is to determine if a particular material has potential as a martial art weapon but some wood species are included to provide comparative data even if they would not qualify for other reasons.

(For those interested in the physics of the test: The strengh of natural woods (used as structural members) is well documented in published data where samples are subjecting to slowly applied loads. This test however is specifically designed to test shock strength as it relates to martial art practice. A hardwood ram, attached to afiberglass spring, impacts equal sized test samples on the tangential surface. The spring's deformation is proportional to the magnitude ofthe applied force. The impact energy is calculated according to the relationship E=1/2ky2. Impact energy can be represented as the square of the calibrated distance that the spring is deformed. Samples are subjected to gradually increasing impacts until failure. The numerical values on the chart represent the impact energy that brokethe sample. Most values are the average of five or more samples ofthe same species. ) White pine is included for reference. American White and Red Oak, both ring porous hardwoods, might have sufficient strength but their open grain presents exposure to damage in those areas. In many cases, very hard and heavy hardwoods such as African Ebony prove to be relatively brittle. Other exotic species such as Greenheart, Blackheart, Blackwood, Leadwood etc all tend to have excellent resistance to denting but low shock strengh. These materials would show little damage at lower impacts but might break unexpectedly with a higher impact. Lignum Vitae, a wood withextraordinary properties, invariably develops checking (either superficial or more severe cracking) due to atmospheric humidity swings and its use a martial art weapon would not prove to be a wise use of resources.(Click here for impact strength chart:)http://www.aikiweb.com/weapons/graphics/graph.gif

Density

Along with impact strength, wood density is a key consderation in weapon quality. It is usually measured as a ratio called specificgravity. When wood floats in water, its specific gravity is less than1 but there are a few varieties, mostly of tropical origin, that have specific gravities greater than 1 and will sink. High density does not necessarily translate into high impact strength. There are several dense woods that have a much lower impact strength than otherless dense ones as shown below. Please review the information in theabove chart "Impact Strength of Materials" and included footnoteswhich describe the impact test and clarify the data in the followingtable.(click here for specific gravity vs. density chart in the middle ofthe page:)http://www.aikiweb.com/weapons/goedkoop1.html

Although high density doesn't necessarily translate into high impact strength, it has a major influence on performance and maneuverability. It is almost always desirable for Baton (policestick) , Yawara (¡short stick ~12"), Kobuton (hand weapon ~5"), Tanto(wooden knife) and other short sticks under 24 inches. The additional inertia is a major benefit in many defensive situations and when the weapon is used for pressure point techniques, dense and harder wood is much more efficient. For these applications, wood with specificgravity over 1 is often best. Bokken (wooden sword) and other longer weapons used in paired practice should be chosen from a material with high impact strength. In some cases, a wooden sword is intended to approach the actual weight of a real sword and higher density materials (specific gravity greater than 1) are required but these weapons should not be used for routine practice. Suitable higher density materials are almost always costly. Most wood with high specific gravity is tropical in origin(the laminated composite shown in the charts comes from reasonably well managed domestic sources but is expensive nonetheless). The most important consideration of all is the possibility of an impact which exceeds the material's shock strength; a situation that becomes more likely with a weapon over 24" in length and relatively slender in diameter like Bokken and Jo. High density materials are harder, with the appearance of being practically indestructable and sometimes won't show damage prior to failure. An unexpected, complete break may create a dangerous situation. The same precautions are advised for very long weapons including Bo (long staff ~ 72") , Naginata(Japanese halberd like weapon ~ 96"), Yari (spear up to 120"), Juken(rifle/bayonet ~ 72") etc. if used in contact with other practice weapons.

Materials

Different materials are appropriate for different weapons and different situations. The following wood selections are described and recommended according to their individual properties:

Shiro Kashi (Japanese White Oak)

Martial artists familiar with Japanese wooden weapons frequently refer to this wood simply as "White Oak". It has a tight but coarse grain structure and like North American White Oak, it has prominant rays which give it a distinctive figured appearance. It's either bonewhite or light tan in color and darkens over time. Shiro Kashidiffers in several respects from North American White Oak. While related, the Japanese White Oak tree is evergreen and owing to its continuous growing season, does not have a conspicuous open grainlike American White and Red Oak. Open grain structure, typical of the so called "ring porous" hardwoods presents soft areas which are more prone to impact damage. Kashi is uniformly hard, has excellent dent resistance and has better impact strength than American Oaks. There are two drawbacks relevant to its use in wooden weapons: It is not stable; weapons of Shiro Kashi will frequently warp due to changes in atmospheric humidity. Also, like other Oaks, it seems to lose strength as it ages. In tests conducted on older samples from wood that had been very strong, the aged material had lost its integrity substantially. The older wood will appear dry and develop cracks usually beginning with a grain separation in areas of repeated impact - a sure sign that the weapon is weakening. Clearly, Shiro Kashi should be considered a good quality utility wood, excellent for several years practice but probably having a limited life span.

White Ash

The most well known and useful of the Ash family is White Ash. The wood is strong in comparison to its weight and is often used for baseball bats, tool handles, oars and paddles. Ash is noted for its stability. It is less subject to twist, warp and dimensional change than most North American hardwoods.Ash is a ring porous hardwood with strongly contrasting spring and summer wood. This characteristic results in alternate, relatively hard sections with softer areas of open grain. Because of this, Ash is more prone to objectionable denting when impacted on its softer areas and is not ideally suited for weapons taking direct impact. Because of its otherwise excellent mechanical properties however, and its tendency to get smoother and improve with continuous handling, it is one of the very best materials for long shaft sections on Yari andNaginata.

Birch

Birch is moderately heavy and hard with good strength. Its appearance is very similar to Maple with an even, fine texture and tight grain structure. White Birch refers to the white sapwood of the species andRed Birch refers to the heartwood of the same tree. Birch grows throughout the hardwood forests of temperate latitudes and is an important commercial hardwood. Its high shock strengh and availability in thick, long pieces, making it a good contender for wooden Bostaff. Naginata, Yari and Juken. In its natural state, its drawbackis its tendency to show impact dents where contact is heavy.Birch is well suited to the production of veneers, In the 1950s, theUS Forest Products laboratory developed a process of drawing resin and dyes through veneer stock and laminating the wood layers under extremely high pressure to produce an enhanced composite product.This material is generically known as Compreg (compressed,impregnated wood). The variation referred to in this publication isthe "Laminated Rosewood Composite" of Kingfisher WoodWorks.

Impact Grade Hickory :

There are at least 16 species of Hickory native to Asia, CentralAmerica and North America. Mixed hickories, appropriate for furniture and cabinet work, are obtainable in lumberyards throughout the UnitedStates. Varieties from New England, the Midwest, Great Lakes and Southwest, including the closely related Pecan Wood, produce lumber comparable in quality to many other North American hardwoods as shownin the preceding impact and density charts. For lack of a better description, the designation "Impact Grade" Hickory refers to a source of regional varieties selected according to subspecies from a small area in the Central Appalachians where trees are selected that yield wood with properties suitable for martial art equipment. Not only is the material unique mechanically, it is also handled much differently than cabinet grade lumber. Common grades of commercial hickory are grouped together. Commercially distributed hardwood is usually kiln dried and hickory, which is difficult to dry, is sawn into into standard 3/4" planks which allow accelerated dry kiln schedules. These thinner planks include (mechanically) inferior species of Northern and Western hickories with the added risk of structural damage caused by faster drying schedules. This special stock however, is cut into thicker slabs of the most premium material from a specific geographical area and slowly air dried. This resulting "Impact Grade Hickory" is either bone white or light reddish in color. It has a flat, graceful grain structure and a smooth texture with good density. Its shock strength exceeds all native and exotic species including the commonly used Japanese WhiteOak (Shiro Kashi). While Oaks appear to become brittle with age,Weapon Grade Hickory retains its toughness. Although heavy contact with very hard materials will cause some denting, normal practice with similar weapons will just create an unobjectionable patina. Even after years of heavy use, it is unlikely to snap into dangerous pieces. Ideally, the best Dojo choice would be the uniform use of this material for paired practice. It's safe, strong, attractive and comes from a domestic managed resource. Just as Kashi is the only wood used in Japan for practice weapons, American martial artists can look to this specially graded hickory as the optimal choice.

Laminated Rosewood Composite (LRC)

LRC refers to a limited, premium grade classification of densified hardwood composite. Made by laminating very thin layers of imbued birch veneer under enormous pressure, it has a stunningly beautiful dark Rosewood color with black highlights, is totally stable and takes a mirror finish.Weapons of LRC have several notable benefits.With a specific gravity of 1.3, its extremely high density and hardness make it ideal for smaller weapons where those qualities are so desirable. It comes from domestic sustainable sources and is an excellent substitute for rare tropical varieties. Since the intersticial spaces and microscopic conduits of the wood are filled with resin, there is little if any exchange of atmopheric moisture and hence no warpage. When skillfully worked, it holds perfect detail and when polished and buffed, will take a mirror like shine without any additional surface treatments. Because it is extremely dense, bokken made of LRC can achieve both the weight, proportion and balance of a live blade. It has excellent physical properties overall and, in the case of bokken, approaches the closest interpretation possible of a sword. It is however, an engineered material with properties different from natural wood and LRC items should be treated more like live edged weapons than those of natural wood. Since the material does not dent easily, it gives the impression that it is much stronger than any natural wood. As the tests show however,it's strength exceeds many of the strongest natural woods but not immensily so. It tends to be edge sensitive and an accidental drop onto concrete, which would just dent most natural woods may cause a more serious chip in the composite material. While there have been many natural wood bokken destroyed when hit with a composite weapon and at least one live steel blade, there have also been a few composite weapons broken and a few instances where a glancing blow at the very end of the point damaged a composite bokken. For these reasons, the LRC is not recommended for paired work involving contact but better reserved for suburi (individual) practice, silent sword techinques, presentation or other special situations. The last consideration, as it relates to paired practice may be saidof any of the very hard and dense materials in general: In a practice situation, many students use equipment that fits their means and their experience. Very hard and heavy wood will certainly do significant damage to the budget oriented weapons that many beginning students start out with. In the interests of safety and good judgement, it is best to engage in daily paired practice with materials that do not cause unnecessary damage to a partner's equipment.

African Ebony

Several tropical hardwoods including African Ebony are extremely hard and heavy but without notable impact strength. Also known as Cameroun and Gabon Ebony, this wood is jet black with occasional grey striping and is the familiar black wood formerly used on piano keys. Because of its density, outstanding hardness and ability to hold detail, it is excellent in small hand held weapons used to apply pressure. Along with other wood of tropical origin, Ebony comes from sources that aren't necessarily well managed, should be considered a limited resource and used judiciously.

Honduras Rosewood

There are several species of natural Rosewood with excellent density, strength, dent resistance and overall physical properties. Honduras Rosewood is usually a dark reddish tan sometimes with prominant streaks of black and purple. It has a beautiful, coarse swirling grain structure with color patterns varying from reserved to startlingly bold. Rosewood is not often available from sustainable sources in pieces suitable for solid construction larger items.Smaller Tanto, Kobuton, Yawara and similar works are often possible. Bokken and Jo of natural Rosewood are highly desirable and extremely rare. This material, like other tropical woods is not recommended for daily practice or casual use due to its scarcity and unique character.

Pau Ferro

South American Pau Ferro (Ironwood) has a beautiful dark tan color often including black streaks and graceful dark figure patterns. It has fine, dense grain with a very smooth surface texture. Pau Ferro,an exceptional and rare tropical wood, is occasionally available inpieces thick enough for solid piece bokken and jo and it makes excellent blade sections for Yari and Naginata intended for presentation and solo practice.

Purpleheart Wood

Purpleheart is available in thick pieces which allow for the construction of largest and longest solid piece weapons. It is sometimes possible to obtain it from managed sources and has some outstanding properties making it especially suitable for staff type weapons like jo, bo etc. It is very hard, and usually displays a straight, uniform grain structure with a somewhat coarse texture. It turns to a clear, brilliant violet upon exposure to light. Purpleheart is extremely stable and lends itself to long, slender weapons where a less stable material would usually develop noticeable warpage. Because it is extremely stiff in comparison to its weight,it gives the user an energetic feel of returning energy rather than absorbing it and for these reasons, could be considered a "conditional wood" - an excellent choice for some situations.

Coromandel Ebony

Also known as Macassar Ebony, this exceptional wood deserves special consideration among the natural woods available for the constructionof wooden swords, staffs and martial art weapons. Because of its superb character, it conveys a unique and unmistakable feeling of presence. Coromandel is strong, hard, has a ideal weight with a fine dense texture. If skillfully shaped and finished, an alive almost reptilian quality emerges with predominantly black with tan figure patterns and occasional subtle but surprising hints of green and other colors. It is arguably one of the most beautiful of all woods. Upon reading this description, it may be tempting to conclude that a fine weapon of Coromandel Ebony is the optimal personal choice for the serious student of the martial arts. Its unrestricted use however, would actually be inappropriate. Acquiring unique and rare weapons of limited natural resources often reflects the enthusiam of aspiring students where, due to the cost and scarcity of this material, is best reserved for special situations - a gift perhaps to a senior instructor from an appreciative dojo.

Osage Orange

No discussion of wood, selected for weight and strength, is complete without mention of Osage Orange, an unusual North American hardwood with a unique heritage. Indigenous to the American Southwest, the wood has a superb strength and was highly prized by Native Americansfor archery bows and is still coveted by traditional bowyers. When freshly cut, it has a startling and unlikely bright yellow color which slowly turns to a subdued orange tan. The tree does not produce much of the dense, straight grained wood which has good mechanical properties. High quality lumber is very rare but the tree is certainly not endangered. Other studies of shock strength sometimes rate Osage Orange as the strongest of all woods. When used in longer weapons for paired practice it absorbs energy upon impact with a surprising springy feel. Under the name Kingfisher Woodworks, James Goedkoop has produced thousands of practice weapons for aikido practice and the swordrelated martial arts.

taken from: http://www.aikiweb.com/weapons/goedkoop1.html

Ben Eble www.woodenbilletknapping.blogspot.com

juichiung@aol.com