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directional strength of wood grain

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This seems like the best area to ask this question...


Let's say I have a block of wood I wish to make into a knife handle, hidden tang construction.


Which makes for a stronger handle, to have the grain oriented with the tang like this?

testB_zpse2499e49.jpg


Or this?

testA_zpsd97b9673.jpg


The black line representing the tang, of course....

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If your using curly maple do it like the bottom illustration. If regular wood I do it as in the top one. I make my tang hole in the wood to fit the tang very closely. With most hardwoods used for handles I am of the opinion it must look good to the eye and they are strong enough to be used either way. Structurally I believe it would be the top method for softer woods.

Edited by GBrackett

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The top method (quarter sawn) is usually stronger, that's why axe handles are made this way. I also find it more visually pleasing, because we're usually looking at the sides of the knife. However, the structural integrity is not a big deal for knife handles, as long as the wood we're using is strong.

So, basically, it doesn't matter much, both ways work fine.

Edited by Collin Miller

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The top one is the strongest.

But both is used and is durable enough, depending on how you do it on the inside.

 

Care must be taken when doing it the second way, especially with spalted wood, or woods that are not very strong, the tang should then extend a lot further than is needed with the above method. Depending on the wood and design on the knife, the tang actually doesn't need to extend very far if the above method is used.

 

We use a lot of patterend woods, so how we saw it is usually the way we think the grain will show the most. So both of these ways are activly used because of this.

 

Oh and remember, but you probably know this, stabilization does not make pieces cut in the second way stronger.

 

//DQ

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As too strength generally with the grain, (top pic), but, as too looks cross grain, (bottom pic), shows more details. I don't recommend cross grain unless the wood has been stabilized because, at each grain is the potential for split out or cracking. Once stabilized the cross grain is less likely to split off and the effect of a piece of cross grain wood, can accentuate the burl or other attributes of the wood grain you will not see when working with the grain!

 

I respectively disagree with the statement that stabilization doesn't make the wood stronger but that is my opinion. The polymers used in stabilizing wood locks into the wood to make it more of a solid piece of wood, especially when using the wood in a cross grain use! Think about it this way when you stabilize the polymers are pulled into all the grain of the wood.

The grain runs the length of the wood and that direction is how the vacuum pulls most of the stabilization material of the wood. However wood has pores as well as the grain which is how the tree basically feed itself.

The polymers being vacuumed into that grain/pores now acts as if you had coated the entire piece of wood inside and out with a plastic sheet. It is this bond that makes the wood now stronger, especially where cross grain use of the wood is applied!

 

Stabilization is done for several reasons. It adds strength, it overcomes the forces that may naturally cause a piece of wood to twist and warp and lastly it is a way to draw color into the woods natural grain and highlight that grain!! However as stated this entirely my opinon!!

Edited by C Craft

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"Stronger" is somewhat open to interpretation. Strictly talking about yield strength, probably the top illustration. However, if you are thinking of durability - especially over time - it is important to know how the wood changes shape with changes in moisture content. Of course stabilization pretty much shuts that down and is more of an argument for using stabilized woods than the whole "strength" issue, IMHO! The hole for the tang needs to hold the tang solidly and yet still have enough space for the wood to expand and contract around the tang. Some sort of adhesive that is flexible enough to move with changes in moisture content, yet still holds solidly, is necessary. The other option is to limit the amount of moisture the wood can absorb with surface treatments or by stabilizing it.

 

wood_movement_01.jpg

 

~Bruce~

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Thank you all for your thoughtful replies.

 

I use a good bit of curly maple and bog oak for handles, and the grain is relatively straight. I've found with both these woods 'B' looks best, it exposes the curl of the maple and the rays of the oak very nicely. However, with axes it is generally 'A' that is considered strongest.

I think the dilemma is that a knife is not used only like an ax... a knife will receive stress from not only front to back, but also side to side, as it will invariably be used for prying, regardless of how light that prying may be (and how often we knifemakers try to discourage it). This side to side force will be along the weakest plane, the area with the least amount of wood... so it may be more of a choice between how would you prefer for the wood to split, side to side or front to back?

A point should be raised about burls in which the grain is chaotic and runs in every direction... I suspect this is a good thing for a knife handle, and this is likely the primary reason most historic hidden-tang knives with wooden handles use burl, the fact it is pretty, and rejected for other uses being happy bonuses...smile.gif I've often noted that, when splitting firewood, the prettiest grain is also the hardest to split.

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That makes a lot of sense about the burl grain being a stronger application for a knife which will invariably be abused in its life. It's sort of like taking your hands and face them palm-to-palm. It's pretty easy to pull them apart. Now lock your fingers and it becomes much harder.

 

As for the original question, I honestly don't think there is a true right or wrong. No matter how you attach the handle you are leaving one plane of movement subject to a less than ideal way to handle certain forces. I think in the end most of us are going to pick the alignment that is more pleasing to the eye because a blade will honestly fail in other places during intense abuse (i.e. Prying) before the handle does. Even if you were to use the handle as a hammer I'm not really sure the grain direction would make much of a difference.

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Ask 10 makers the same question and you get 10 different answers! The funny part about I think Bruce and I were speaking basically about the same thing. I have been thinking of this post since earlier today and the question is one of those that there is no straight answer too. If you treat the question as a legal document and read nothing into and take nothing away from it

 

The cut and dried answer is basic to wood and with the grain is stronger. However if you take the question as too how it pertains to wood used on a knife handle then all bets are off and it becomes a product of use and interpretation.

 

A stabilized wood takes the variables pretty much out of the game. As noted by Bruce the things that make wood, wood are pretty much altered to a higher degree of use. It allows for cross grain looks without losing strength, it allows for coloration, as well as the other attributes of no warpage, no twisting less come and go.

 

So you find yourself going back to, "what was the question"?????? A lot of the answer is in perspective of how am I going to use this piece of wood and what I want to accomplish!

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I've run across references to using wood from the roots for knife handles a few times in the past as well. The structure of the root wood is different than the rest of the tree. Not quite sure how that affects things but, I suspect it doesn't absorb moisture the same way. I've not had time to try any as an experiment but, am somewhat intrigued.

 

Dense, oily, hardwoods are another solution. They are naturally stabilized, being so full of oils.

 

Another thing to consider is that, historically, handles would have been made from branches and small diameter trunks. As long as the center pith is removed, the piece can be dried without cracking or splitting too much. This construction would be much stronger than both A and B, above.

 

~Bruce~

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I've run across references to using wood from the roots for knife handles a few times in the past as well. The structure of the root wood is different than the rest of the tree. Not quite sure how that affects things but, I suspect it doesn't absorb moisture the same way. I've not had time to try any as an experiment but, am somewhat intrigued.

 

Dense, oily, hardwoods are another solution. They are naturally stabilized, being so full of oils.

 

Another thing to consider is that, historically, handles would have been made from branches and small diameter trunks. As long as the center pith is removed, the piece can be dried without cracking or splitting too much. This construction would be much stronger than both A and B, above.

 

~Bruce~

Very interesting, this is something I've not tried, and I have some boxwood branches that should be quite dry by now.

I know that roots have the convoluted grain we knifemakers look for when picking wood, but was not aware of structural differences. I have a root from a plum tree, but it needs to dry for a few more years.

I tend to avoid stabilized wood, at least for the majority of knives I make... being historic types, it doesn't seem appropriate. For more modern designs I don't mind using it. As much as I like African blackwood, it is hard for me to justify using African blackwood for a seax handle, or any other tropical wood for that matter. My obsession with the seax is what lead me to this question, because the handle strength is entirely dependent on the wood. I've never been able to bring myself to use ferrules or wire wraps on type IVs, but I'm considering it for the larger pieces to strengthen the handles. I've never had a handle fail, but I never want to have one fail either... perhaps its my tendency to want to overbuild everything.

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Where is a good place to send wood to have it stabilized?

 

I've just been given a maple for fire wood and it's full of spalt, curl, and bird's-eye.

 

Can't just burn it all.

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That's the same reason I was curious, given that I work in historic styles, prefer old-school handle woods native to the blade's place of origin, and I consider stabilized wood just a form of plastic (my own opinion for my own work, not knocking anyone else's choices! ;) ).

 

Interestingly, did you know the traditional handle wood for baselards is vine root and that for ballock daggers is ivy root? As in grapevine root and English Ivy root. I have yet to try those, but I'd like to one of these days.

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I have had a handle fail before, when using cedar, and a very over sized tang slot, ad gorilla glue as a resin, one of my first knives, I don't know what I was thinking!

I split wood with an axe quite a bit, and I definitely agree that the twisted, pretty grain is a total chihuahua to split (I live with a chihuahua)

 

As much as I like African blackwood, it is hard for me to justify using African blackwood for a seax handle, or any other tropical wood for that matter.


It's a widely excepted theory that the Norse went as far as the Middle-East for some of their steel. And traveled as far as Africa, so in a hypothetical theory, with no shortage of fantasy, the Scandinavians could have had African Blackwood. ;)

Possibly small branches were used because of the fact that they're easier to work with? Perfectly straight grain, good workable size. Besides, it's probable that common people would buy the blades and then make their own grips, for a common seax. Normal people wouldn't have the proper tools to process large, hard trees such as oaks, walnuts, and maples. I know it's possible to process such trees with only an axe, but is it really worth it when a simple branch would be so much easier?

I have worked with sumac root, for an archer's ring that belongs to a friend of mine, and it was a lot different than normal wood, in a good way, too.

I have to agree that stabilized wood is another form of plastic, but it could save a lot of pain if working a burl, with all the voids and such. I must confess, I've never worked with a real burl, or stabilized wood, however I can't say that I would like to, because I like to carve and whittle my handles, and from what I've seen, you pretty much have to work with saws, grinders, rasps, and sanders when working burl or stabilized wood. I would be very happy to be corrected though.

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Where is a good place to send wood to have it stabilized?

 

I've just been given a maple for fire wood and it's full of spalt, curl, and bird's-eye.

 

Can't just burn it all.

Some of the prettiest wood I've used came from the firewood pile...

 

I hear K & G are some of the best at stabilizing wood, and I've used their wood before. I've also heard good things about WSSI, but I've never used wood from them.

 

 

Interestingly, did you know the traditional handle wood for baselards is vine root and that for ballock daggers is ivy root? As in grapevine root and English Ivy root. I have yet to try those, but I'd like to one of these days.

Very interesting. I've dealt a little with wild rose, they sometimes have an impressive root-ball, and can be a nuisance when they grow where you don't want them to... I may have to collect a specimen next time the opportunity arises.

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I'll give you something to think about which is basically saying the same thing as others here. In your ring-porous hardwoods like oak, hickory, ash etc., the weakest part of the annual rings is the part which grows each spring while the sap is going up in the tree. This is what appears to be the very porous sections or rings when you cut the wood cross section. The wood that grows during the summer or main growing season is the part of the annual rings that appears to be more dense. This is the part of the wood that holds the most strength thus determining which direction the wood is most strong. The strength in this direction can be as much as eight times stronger. With diffuse-porous woods like maple the strength variance is much less.

 

In either case I would recommend using the wood in the handle to be oriented so as to be the most attractive as a properly made handle shouldn't have strength problems to the degree that it becomes a concern.

 

Just my $.02.

 

Gary

Edited by Gary Mulkey

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