Primitive Archer
Main Discussion Area => Bows => Topic started by: richgibula on December 19, 2022, 05:14:06 pm
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I have the privilege of obtaining a large piece of Arizona ironwood. I have previously made a bow out of a piece of mesquite which performs wonderfully, but never ironwood. Does anyone know about the performance of ironwood, like how thick it needs to be (very hard and heavy wood) or how well it will hold together?
This will be a bit of investment since the wood will be rough on the tools and it is hard to handle due to its weight. I will need to plan a lot.
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Well, what do they call ironwood in Arizona. Around here, it's American hornbeam (blue beech).
In the PNW they're talking about ocean spray.
Seems like there's one everywhere. I know whatever the Australian version is was very dense if I recall correctly from my guitar building days.
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This is what I found. I don't think that its related to beech:
Common Name(s): Desert Ironwood
Scientific Name: Olneya tesota
Distribution: Southwestern United States and Northwestern Mexico
Tree Size: 20-30 ft (6-10 m) tall, 1-2 ft (.3-.6 m) trunk diameter
Average Dried Weight: About 75 lbs/ft3 (1,210 kg/m3)
Specific Gravity (Basic, 12% MC): ~.97, ~1.21
Janka Hardness: 3,260 lbf (14,500 N)
Modulus of Rupture: 10,880 lbf/in2 (75.0 MPa)
Elastic Modulus: No data available
Crushing Strength: No data available
Shrinkage: No data available; reported to be very stable in service
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Workability: Very difficult to work on account of its density. High cutting resistance. Desert Ironwood is usually restricted to very small projects, though it takes a good natural polish and is very stable in service. Turns, polishes, and finishes well.
I just wish I knew something about the use in bows.
Its is considered the 8th most dense wood in the world.
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No experience with it but commenting based on the numbers. It appears to have similar statistics to Ipe but has a comparatively low modulus of rupture - substantially lower than Ipe, Osage, hickory. I would probably consider treating it like Ipe and putting a hard backing on it, but I’d really like to know it’s crushing strength though to be sure about that. But nothing beats practical experience - some woods just surprise in a bow context.
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Use a sharp ax, and rough rasps to get it to floor tiller, and a sharp knife, and sand paper. That works best for me with the blue beech of the east. Make a bow from it . You may end up liking the wood. I wonder how many other woods are going to be called iron wood before to long? Good luck.
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A guy on here made a bow out of some maybe 20 years ago but that's all I remember of that plus it was on another server so you won't find any info on it...I know not much help
P.S. I believe his username was Arquerero
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Amazing that you have found a piece long enough and straight enough for a billet, let alone a full length stave. I've only ever seen photos of AZ ironwood, timber in small craft sections. Most of it is twisty/gnarley, with some clear sections in between, useful for knife handles.
Absolutely beautiful wood, really dense and heavy, looks a lot like cocobolo.
I would second the use of a hickory or boo backing when using wood that is a bit of an unknown quantity. Not all dense woods have the same physical properties in reality, when it comes to bows. Some that look really good on paper can be weak in tension or compression. A backing will stack the odds in your favour
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Thank you everyone for your comments. I found this piece, about 4" X 6" X 5 ft, at a lumberyard that specializes in mesquite. That's where I got my mesquite for a bow I made. They inherited the ironwood when they purchased the lumberyard almost 20 years ago. Since then, there has been a ban on new harvesting, according to them. That has something to do with the fact that ironwood here is a nurse plant for a lot of local plant germination, including saguaro cactuses
There were only a few large pieces and mine has large cracks where I will have to work out where and how to cut ut. I expect to lose 1 or 2 bandsaw blades in the process. I will likely have to splice two pieces together given the shape and cracks. I am also hoping to do something with the pieces that will remain. If I pair side-by-side pieces, it will probably tiller easier.
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My Ironwood pic.
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More pic's of the billets please?
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Take Tim Baker's approach. Cut a small sample from an area that is not going to be part of the bow, thin that piece enough to try some bending experiments. Nearly all woods will fail in compression just before they fail in tension, provided the tension grain is uncut.
Looked at another way, most of a stave is totally wasted in the making of a bow. Where that wood is so beautiful, it's a shame to turn most of it into useless chunks and shavings in order to make a bow that will not perform better than one of Osage or yew.
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Desert ironwood will split and crack most likely blow up in you face, it makes pretty knife scales that will split if you drop it unless it is stabilized.
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It might be a brittle wood, but the poster is going to back it, so tension won't be an issue. Compression resistance is another matter. It is a risk as some really dense woods don't take compression as well as their density would suggest in theory. eg purpleheart.
I've never really understood the need to stabilize a heavy wood like this, unless it has checked in drying or is knotty. It will sink in water rather than float. This means there is negligible space in the pores, not much empty space for the resin to replace. A medium or light wood will benefit much more in terms of strength by stabilization because all the empty space will be filled.
You sound like you are speaking from actual experience regarding IW, when dropping it. Do you know what method of tang construction was used?
Some woods defintely are brittle when it comes to shock. Nothing beats hickory for an axe, or sledge handle. Several other woods like ash and beech, oak are good too. The thing they all have in common, is that the wood compresses from a missed strike, rather than immediately starting to splinter.
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I have only a beam, no billets.
Thanks for your info.
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I have used an epoxy treatment that works on softer woods. I used it a lot on things like walking sticks made of yucca stems to improve their reliability and prevent unexpected cracking or deep scratches.
The ways it works is to mix up your favorite strong epoxy. I use West Systems or Pro Set which have a tensile strength in the range of 8000 to 11,000 psi. You mix it well, then you add enough acetone to make it thinner than water. How much this takes depends on the epoxy viscosity and temperature.
Rub the mixture into the wood until it does not absorb any more. Wipe down any access on the surface unless you want a glossy look later, but it might be irregular. It will take days to dry because the acetone first needs to evaporate from inside the wood, then the epoxy can gel. If you want to coat it later, do a light sanding to improve adhesion. Remember that this mixture is very flammable.
I am sure that this improves compression strength on a soft walking stick, but I have no idea what will actually happen on a very hard wood. I am sure there is some "case hardening" going on and there will be better scratch resistance since the coating penetrates deeper than a varnish. Of course, these is not a "primitive" solution to anything but it is a neat trick that has made my yucca walking sticks survive over a decade of use. (It took a long time to find ones that have the right thickness, length and nice looking curves and then apply leather grips.)
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I have been looking for a handle wood and I found this piece of firewood that I got from family in Colorado. I am not sure what it is but it is most likely Russian Olive. The only other firewood out there was a pine. Any other ID ideas?
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Looks very close to laburnum
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Since this is a board and very hard, are there some recommended dimensions that would be best for a bow? I have made bows from 68" to 48" but not from a board. I am assuming I will use a strong backing.
Thanks for your help.
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Dimensions??? I'd go around 1 &1/4" maybe 1&3/8" wide for a flatbow as you are dealing with an unknown quantity, in regard to chrysalling.
If it holds up you can always start to narrow the width rather than the belly whilst tillering.
Length, start at 68" if you have the length in your billets. You can always pike it later if necessary. Glue in around 2" of reflex with the backing.
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Thanks Hamish. Based on the continuous parts without splits, I can make up to 1 1/2 inches wide but I will have to butt-join 2 halves together for length. I have done that part successfully before. With that I can make it to 68 inches.
I am worried that its such hard wood that the draw weight will be huge.
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I am worried that its such hard wood that the draw weight will be huge.
The point of tillering is to balance the to limbs and to get to the desired draw weight. So there's no reason why the draw weight should be huge other than by the choice you make. In fact, your bow will be hardly any thinner at 50# than a regular hardwood bow.
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Since I am trying to conserve the Ironwood, how thick of a piece do you think I should start with when I cut it to shape the bow?
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In reviewing this thread, I see suggestions for a different backing, and some discussion of a different wood for a handle.
have you considered laminated designs that minimize the use of the ironwood, reserving it for just the belly portion of each limb? the ironwood would only need to be a lam 1/3 of the limb thickness or thinner depending on the core lams, and need only be long enough to extend through the working part of the limb and into the fade.
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Interesting thought. The other wood needs to be contrasting. I wonder what I can find in a lighter color, maybe maple or hickory?
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If you use boo for backing, maple would make a nice core wood, contrasting with the AZ ironwood. If you used hickory for a backing, then maple wouldn't look as good(less contrast). Purpleheart or wenge would look good, as would cherry.
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Good thought. I wonder if there isn't a back wood that would not need additional backing. I guess I could always use a bamboo stave.
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with the ironwood being so heavy, even hickory would be lighter and could serve as a backing and a middle, perhaps a a single piece with the the ironwood lam on the bellyside. you would of course want to pick a design that would make this construction easy. long easy ramps into the handle, etc.
maybe non working stiffer tips if you are limited in ironwood lam length......
with all the experience available at this forum, opening a different thread exploring design possibilities for such a bow might be interesting
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I am not sure what to say on a different thread for design purposes that is not already here, but I love the thought of design ideas.
The longest section I can cut out of the Ironwood piece with the proper grain orientation is about 51 inches before I hit the first split. At that length, I can make the piece very thick or make two thin pieces.
Alternatively I can splice two shorter pieces, originally side-by-side in the board, to any length you would want in a bow.
If I use a backing wood then the Ironwood part can be at 51 inches while the back could be longer.
I am open to any design ideas.
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reference pic
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I am not sure what you consider the proper grain orientation, but I dont think flat sawn is particularly called for with a belly lamination. In fact if there any waviness in the ring lines such that the belly lam were to have any runouot when viewed from the side of the bow. I would think a rift sawn or quarter sawn lam would be better for the belly.
would it be possible to get a few better pics of the log such that any proposed cuts could be explained better. I suppose knowing which tools you are going to cut the beam with would be useful for those wishing to advise
have you considered a carbide tooth band saw blade? expensive tooling for sure, but sometimes the costs are justified when the right project comes along.
as far as bow designs go,
a longer narrower bow might be easier if its going to be difficult to get clear pieces for a belly lam. two shorter lams could be butt jointed under the handle making the length needs fall to 32"-- 36 "
this forum member posted quite a few construction detail photos on elb type lam bows which are still on the server.
http://www.primitivearcher.com/smf/index.php?action=profile;u=534;area=showposts;sa=attach;sort=posted;start=0
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Its hard to see on a photo but the piece is about 3 X 5 inches X 4 feet. The grain appears flat on the narrow side, facing left, and cross cut on the wider side, facing right. There are several splits and cracks. The 3 inch wide side (facing left) would be the belly or the back.
I have made bows that needed to be spliced at the handle in the past. The question is what should the geometry be in a situation where the wood is really hard and heavy. Some people have said that the bow should be thinner or narrower than if the wood was softer. This is the info I need. This wood is so dense that I have trouble lifting this piece to carry it in the garage.
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The grain appears flat on the narrow side, facing left,
I think I can see islands and flame tips in the rings on the sawn side (left) which would indicate the runout condition to avoid. just guessing as I cannot see well the ring lines on the right smooth side, but you would want to trace a ring line from top to bottom there and see if it is parallel to the front of the log or the sawn face on the back? (left)
were you to cut a lam from the smooth side, you could skew the orientation of 2 half length lams in the bow such that the ring lines ran closer to straight more full length pics showing each side plus an end view would help and allow someone to photoshop a recommendation.
not sure which geometry you are asking about, but any particular wood will only bend so much before being damaged or taking set, some species more than others. How much being primarily dependent on thickness. if the wood is denser, it will make for a higher poundage bow compared to the same width/thickness section from a less dense wood.
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If the wood is 3" wide x 5" high, I would rip 3" wide x 1&1/8" section (off the 5"height). Then I would rip that piece down the middle of the width into two pieces, prolly around 1&3/8" -1&1/4", after saw kerf, and careful clean up.
Not worried about the feathering of grain on the base, its fine ringed, but at a slight angle(doesn't look too severe, especially when backed). Willie's suggestion is a good idea, so you can check how much runoff it actually has, and adjust to it if necessary.
Keep note of the ends, and which face is top and bottom. Glue up like a split pair of sister billets, handle from the same end, top and bottom faces matching so you can insure liklihood of automatically having the same properties in both limbs, of the glued up bow.
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This is very helpful. I will try to clean up the surfaces for a better view and show a pic before I do anything. I like the idea of sister staves to get a symmetrical flex.
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As suggested, I got some more photos. I planed out the mill marks, sanded it smooth and wet it with alcohol to bring out the grain lines.
There is one of the end-on view. Its a little out of focus, but you can see grain lines. The narrow side view shows the flat looking grain and the rays which are longitudinal. The wide side shows the very narrow grain where it was cut more perpendicular to the flat grain, although the piece is obviously from a small tree, as you would expect from a desert Ironwood.
I hope this visualization helps to recommend an approach to cutting this beam for a bow.
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Narrow side
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Wide side:
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My guess is that I should cut off a piece from the narrow side, which is 3 inches wide and cut that in half longitudinally for two 1.5 inch bow arms that I would join at the grip.
The next question is how long and how thick to make the arms given the hardness and rigidity of the wood. Should the bow be thinner and shorter than typical for the draw weight? If I start out too large, then I waste ironwood. If I start out too thin, you can't make it thicker.
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As suggested, I got some more photos. I planed out the mill marks, sanded it smooth and wet it with alcohol to bring out the grain lines.
There is one of the end-on view. Its a little out of focus, but you can see grain lines. The narrow side view shows the flat looking grain and the rays which are longitudinal. The wide side shows the very narrow grain where it was cut more perpendicular to the flat grain, although the piece is obviously from a small tree, as you would expect from a desert Ironwood.
I hope this visualization helps to recommend an approach to cutting this beam for a bow.
the end view is informative. cool looking wood btw. which side, in the end view shot, is the one facing the viewer in the pic with the white truck ?
one more pic would help.
would it be possible to trace a ring line with a contrasting marker, for the full length on the narrow right hand side (of the end view pic)? seeing how the ring lines run along the full length of the beam would help us advise better
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In the second shot, you are looking at the narrow end which is on the left side of the end view. The third shot shows it from the top of the end view. I cannot cut the right side, looking from the end view, due to cracks and splits further up. I can really only cut the left and top sides because of those cracks, unless I cut short pieces.
I need to first work out the cut orientation and then the thickness and length of the bow arms.
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On second thought, I suppose I could cut it on an 45 degree angle, judging from the bottom shot, to make the bow wood with the flattest grain facing the back of the bow. It would maybe improve the wood function but it will waste the most wood.
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would it be possible to trace a ring line with a contrasting marker, for the full length on the narrow right hand side (of the end view pic)? seeing how the ring lines run along the full length of the beam would help us advise better
and/or also trace a ring line from end to end along the bottom face of the beam as shown in the end view.
without knowing how the ring lines run among the usable length of the pieces to be spliced, it is futile to try to advise
referring to the sketch of the boards I posted earlier. the sections you utilize should have straightest ring lines possible down the length of the board, on two adjacent sides
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I did the grain highlight photos. This one is the end grain.
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This grain highlight photo is the left side of the end grain.
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on the side of the beam you have marked out rays, which in the case of your wood, are much more apparent, but they dont tell much about the direction of the grain.
http://www.primitivearcher.com/smf/index.php/topic,68359.0.html might be helpful.
the ringlines in your beam are quite fine and may be very difficult to follow. As noted in the topic linked above, the bowyers bible has a good explanation and some drawings also .
if your bow stave has much run out, which I think might be the case, it is at risk of breaking. this is why I suggested considering just a belly lam of mesquite. If the best part of the bow has straight grain, and is of a known bow wood like perhaps hickory, your chances of the bow holding together are much improved. If your mesquite is harder than the hickory you may realize a gain in performance for having it on the belly face. alternately you might be able to make a slightly higher poundage bow compared to a similarly sized all hickory bow, or a slightly smaller bow of the same poundage.
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The rays are longitudinal, the grain lines are the ones I marked with the black marker. They intersect with the longitudinal grain lines on the top side in the end image.
I don't intend to shave this wood with a draw knife. My arms would fall off. I hope to orient the bandsaw cuts in the best direction possible and use a backing. The other questions that remain are the width and thickness of the bow arms compared to a softer wood. Should this be thinner, narrower, wider than hickory?
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rich,
Sometimes terms about wood characteristics are confusing as different trades and usages speak of some things interchangeably. For me, ring lines represent the annual growth rings on a tree. your beam has very thin growth rings and you can see hundreds of years of growth rings in the end view. I guess a furniture maker would call this a fine grained piece of wood, but grain means something a little different to the bow builder.
Each years growth consists of long thin cells or fibers. We, as bow builders, would like to have a stave where the fibers grow straight up and down the tree, but sometimes the fiber orientation is wavy as it goes up the tree or the fibers are laid down with some spiraling. the run of these fibers is what we call the grain these fibers are continuous only in a single years growth.
when working with a sawed log, we have to try to do whatever we can to not cut across the fibers when roughing out a bow. as we cannot actually see the fibers we can only make a best educated guess as to how they lie in the board. violated ring line are one of our best indicators. your russian olive photo shows many violated rings, as it is easy to see in coarse ringed wood especially in the flat sawn condition. rings seen in a rift or quarter sawn cut take more care to visualize the run of the grain.
I highly suggest reading the traditional bowyer bible check out page 19 in both volume 1 and volume 2
https://shop.primitivearcher.com/product-category/books/?product_orderby=default
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Thanks for your help. I read this book, or at least selections. I don't know how closely I can keep within a grain line with a bandsaw, particularly when avoiding knots, having grains at an angle to the surface and having wavy grain lines.
Having said that, I am still wondering about how thick and wide to make a bow out of wood like this.
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your cuts should follow the grain and flow around knots, the stave becoming wider in those areas
not knowing your bow design or length, proposing dimensions is hard to guess
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So let's say that I use a thin bamboo backing, 1.25 inch wide at the handle, 64 inch length nock to nock. Is there a way to estimate thickness and tapering for a 60 lb draw for a wood this hard? Let's assume this grain lets me put in a little reflex.
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It's hard to see the grain from a distance, so I highlighted it with a marker. I marked a proposed cut for the bow, following the grain lines where I could. I had to start a distance from the end due to knots.
The problem is that there is a transition at the arrow where I will have to cross grain lines. Since this is a board I don't know a way around that. Is there something I can do with that or should I pick a different part of the board. I like the current selection because of the reflex.
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The limb shape you have drawn out, is the look for the bow want, but that is not how you achieve it. A bow of that shape, especially if you use a backing, is derived from the form you use to glue up your laminations. The grain where your reflex/ recurve occurs doesn't look to be anywhere as curved as the drawing, and will therefore be a weak spot.
I would use a long rule and mark a line that broadly follows the average run of the grain. From what I can see, the grain runs out of parallel from the edges of the board. Starts in the middle of the left side, and runs at an angle up to the right side. It looks to be straight enough except at each end. With a backing and perhaps a core that amount of run off will be acceptable.
I would just saw off straight boards from the new drawn line.
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Thanks for your input, Hamish. I like your approach. The only thing I would add is that the picture is hard to see on the low resolution required by this site. So, I did a closeup of the right curvy area to show the grain direction.
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can you show the ring lines marked out on the side view turned 90 degree? pick a ring about an inch and a 1/4 down from the outermost ring of the tree.
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This is a 90 deg rotation view of the last image. The arrow from the last shot would be on the left side and the tip is marked.
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So I sanded the board and shellacked it. then marked the grained carefully. I did this for my future cutting accuracy, but I noticed that there were queries to me on this wood but no responses.
Here are the pics of my efforts:
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Next to the right:
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Next to the right:
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Next to the right:
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Next to the right:
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This is a composite for clarity but the details are hard to see:
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I plan to cut a section, following the grain for about 34 inches. Then cut it in half longitudinally to make 2 pieces 1 1/2 inches wide and do a half-lap joint at the handle end with a couple of dowels. Then I have to decide about the backing.
The remaining question I have is the bow arm thickness. Does anyone have an ideas about that with such hard wood?
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bow limb thickness: that's just the whole process of tillering. Take off wood, bend, indicate where you need to remove wood, repeat. If you're gonna back it: 15 mm is more than enough thickness for any bow. You'll probably end up at around 1 cm.
But honestly, this looks like a hell of a difficult project for a first bow, with wood you don't know is even any good for a bow. Yes it's extremely dense, but that doesn't make it better as bow wood per se: it just means it allows narrower limbs. Which isn't necessarily easy. I'd put it away, make a bunch of regular bows first, and then maybe look back at this piece.
my 0.02 €
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Thanks JoachimM.
I have made a bow from laminated bamboo and a mesquite bow before. The mesquite bow was 68 in and has an over 65# draw. I had to use fiberglass backing because it could not be used without a very strong backing. I wanted to have a little less draw weight since I have developed a muscular disease that makes this bow hard to use. I wanted to prepare the wood better and learn to follow the grain.
This is the mesquite bow pic. I wasted a lot of time and mesquite to make it. I was hoping to do a lot better with the Ironwood.
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Another question is: what is the best taper? I was of the impression that softer woods will work best with the taper #1, that is, right at the end and the hardest woods should be the slowest taper (#3).
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for a bow limb to bend evenly or to be stressed equally and not be overstressed or hinged at any point it must be tapered
tapered in width or tapered in thickness or some combination of both. changing the width taper only means you will have a different thickness taper to get the stress even. this principle is a mater of physics.
whether the wood is soft or hard, strong or weak, brittle or elastic all affect the thickness or width or limb length or draw length
ie a characteristic of materiel qualities
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Thanks for the reply willie. I understand the physics and tillering concepts. I was thinking that there were recommendations based on the wood type. I have seen people make bows out of very soft wood but they would make wider and longer bow limbs to increase the mass to generate more recoil from the draw. I thought that there were reverse concepts for very hard woods.
I tried to review the pics of osage bows on this blog. Since that is a hard wood, I thought that the designs would have something in common with what I am trying to do. Unfortunately, most of the pics were removed and I was not able to see too many successful construction images.
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I have. been reading around and wondering if, since it will be hard to follow a growth line, should I shoot for a wider bow rather than a more aggressive taper?
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3500+ views and no more advice?
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I think I understand your concern about thickness tapering the ironwood, if you mean that it might expose more grain runoff in the already wavy ringed ironwood.
if you made a bi-lam with the ironwood belly at 3/16 to 1/4 ", and had a hickory board lam for the back. you could start with the hickory at any thickness and tiller from the back
pryamid would require less thickness taper and might be preferable
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Thank you willie.