Testing the strength of different wood species(woodgears.ca)
woodgears.ca
Testing the strength of different wood species
https://woodgears.ca/wood_strength/
79 comments
Wow, super neat system (i love forgotten analog techniques like these)
https://www.youtube.com/watch?v=MBwP3YOxw3I someone made a video about it
https://www.youtube.com/watch?v=MBwP3YOxw3I someone made a video about it
When I came across that video last year I sent an email to the creator, but never got a reply.
I made some of my own edge-notched cards using a computer-controlled stencil cutter. Here are some pictures - https://twitter.com/nathanbroon/status/750465911241502721 .
I had the idea to present it at a Chaos Communication Congress. Then life (a.k.a having kids) intervened.
I made some of my own edge-notched cards using a computer-controlled stencil cutter. Here are some pictures - https://twitter.com/nathanbroon/status/750465911241502721 .
I had the idea to present it at a Chaos Communication Congress. Then life (a.k.a having kids) intervened.
There's an episode of Grand Designs (season 10 or 11 IIRC) where the couple building the home chose Japanese larch for the cladding for their home in Wales. The specialist lumberyard used some sort of handheld tool to measure the density of the trees (harvested in Wales) and it was extremely strong ... but the show also noted the strength could vary widely from batch to batch, depending on variables such as age, soils, etc.
Some details: http://www.cilfiegansawmill.com/forestry-wales/
Some details: http://www.cilfiegansawmill.com/forestry-wales/
From what I've heard from experienced carpenters and wood millers, growing conditions are a huge factor, as you want slow growing trees that have compact tree-rings. Also if you can get a wood piece with the core wood running through the entire length, you'll have a stronger work piece.
The strength of slow-growth vs fast-growth wood depends on the anatomy of the tree in question. Ring-porous woods (oak, ash) have (as the name suggests) growth rings that have a very distinct ring of pores running the length of the wood.
That means that fast-grown oak or ash is actually stronger than slow-grown. As you look at a cross section of the wood, slow-grown wood has a much higher amount of void space than fast grown.
As I understand it, the southern longleaf pines are the opposite. Because of how their growth rings are formed, they have alternate layers of more and less dense wood. Slow-grown has a higher percentage of the dense, stronger wood. On this point I'm speaking from reading, not firsthand knowledge. The only SYP we get up here in the northeast is pressure treated. PT works totally differently because it's so damned wet and I don't use much of it either way.
That means that fast-grown oak or ash is actually stronger than slow-grown. As you look at a cross section of the wood, slow-grown wood has a much higher amount of void space than fast grown.
As I understand it, the southern longleaf pines are the opposite. Because of how their growth rings are formed, they have alternate layers of more and less dense wood. Slow-grown has a higher percentage of the dense, stronger wood. On this point I'm speaking from reading, not firsthand knowledge. The only SYP we get up here in the northeast is pressure treated. PT works totally differently because it's so damned wet and I don't use much of it either way.
One thing that saddens me in the region I live is the lack of diversity in forests and therefore also in lumber selection. Quickly googling up some stats, 65% of forests are pine and 24% spruce. Only major hardwood would be birch (9% of forests), and its usually not available as lumber afaik.
One of my dreams (in the category "if I were a billionaire") would be to buy some large piece of land and plant all sort of interesting trees to create a sort of fantasy forest.
One of my dreams (in the category "if I were a billionaire") would be to buy some large piece of land and plant all sort of interesting trees to create a sort of fantasy forest.
It’s not what I would call common, but people do it.
As small agriculture consolidates and goes out of business, some wacky rich guys buy farms and turn them in legacy tree farms.
I grew up and went to school in a rural area of NY, one of my old friends maintains properties like this for clients as a side gig for his farm work. The area was selected to benefit from climate change.
In one case, just in terms of black walnut trees, when mature in 50-60 years, there is the equivalent of $10-12M (at todays prices) worth of timber for the owner’s descendants. The trust structure saves cash on taxes as well.
As small agriculture consolidates and goes out of business, some wacky rich guys buy farms and turn them in legacy tree farms.
I grew up and went to school in a rural area of NY, one of my old friends maintains properties like this for clients as a side gig for his farm work. The area was selected to benefit from climate change.
In one case, just in terms of black walnut trees, when mature in 50-60 years, there is the equivalent of $10-12M (at todays prices) worth of timber for the owner’s descendants. The trust structure saves cash on taxes as well.
For black walnut - there's a spot that I've seen that does this. Not too large, but its been there for about 30 years. https://www.google.com/maps/@43.1517879,-89.6032561,3a,75y,3...
That plot is (measuring, mathing)... about 3 acres. https://www.profitableplantsdigest.com/growing-walnut-trees-... puts it at $100k/acre.
> For those with time and patience, a living legacy of walnut trees can be a priceless gift for children and grandchildren. According to professional timberland investors, the average return from a stand of walnut trees is 14 percent a year, with no taxes due until harvest. That beats returns on bonds, stocks and most other investments handily, and with intercropping, growers can even produce an income while the walnut trees continue to grow.
That plot is (measuring, mathing)... about 3 acres. https://www.profitableplantsdigest.com/growing-walnut-trees-... puts it at $100k/acre.
> For those with time and patience, a living legacy of walnut trees can be a priceless gift for children and grandchildren. According to professional timberland investors, the average return from a stand of walnut trees is 14 percent a year, with no taxes due until harvest. That beats returns on bonds, stocks and most other investments handily, and with intercropping, growers can even produce an income while the walnut trees continue to grow.
Yes, and if you’re rich, there are many ways that you can leverage tax incentives and trusts to create perpetually tax free investments. Unfortunately, US tax law is creating a new feudal aristocracy, with food production shifting to latifundia like models, and the aristocrats wielding tax exempt dynastic wealth.
Even for normal people, some of these properties, especially defunct dairy farms are tragically cheap and not too polluted. My dad bought one for hunting and fishing purposes when he retired and made a modest income by leasing the land for hay. Not much, but enough to pay the taxes.
Even for normal people, some of these properties, especially defunct dairy farms are tragically cheap and not too polluted. My dad bought one for hunting and fishing purposes when he retired and made a modest income by leasing the land for hay. Not much, but enough to pay the taxes.
Isn't this just traditional ugly mono-culture forestry?
wow that is a really interesting investment vehicle. provided your descendants don't mess up and sell the land
If you're looking for this kind of product, it's usually best to go to specialty milling places (small studios that will mill custom lumber - eg traditional beadboards etc - they often have unusual supplies) or a dedicated hardwood supplier ($$$). These options may or may not work/exist where you live, but around me I can source some specialty hardwoods and softwoods (eg tamarack[1]) that definitely aren't available at regular shops.
[1] https://en.wikipedia.org/wiki/Larix_laricina
[1] https://en.wikipedia.org/wiki/Larix_laricina
You don't really have to be a billionaire. Land is pretty cheap if you're far away from a city. And people start similar permaculture and agroforestry projects all the time.
Also the reason for more monocultural forests like that is because the soil is high quality. If you had really low quality soil (like in the Amazon) you would have developed a lot more biodiversity
Also the reason for more monocultural forests like that is because the soil is high quality. If you had really low quality soil (like in the Amazon) you would have developed a lot more biodiversity
Other species won't necessarily thrive in a situation like that. You describe a fairly cold tolerant mix there, for instance.
Here in Michigan the species diversity of our forests has been declining due to disease. Elm, and now Ash and Beech have all been dramatically impacted by imported diseases.
Here in Michigan the species diversity of our forests has been declining due to disease. Elm, and now Ash and Beech have all been dramatically impacted by imported diseases.
Not true. I used to work at a lumber company. If you're in North America, you can usually buy some kind of hardwood. For utility lumber, they probably can't tell you what kind of hardwood it is, but it will be hardwood.
> If you're in North America, you can usually buy some kind of hardwood
That's the thing, I'm not in NA, so pretty much any hardwoods available here are "exotic" imports.
That's the thing, I'm not in NA, so pretty much any hardwoods available here are "exotic" imports.
How could they not tell what type of hardwood it is? In my (tropical) country, different timber looks very different, and anyone working in hardware or construction should be able to tell on sight what type of tree a plant came from.
https://woodidentification.net/about/
"Identifying wood is not easy for a number of reasons. First, there are hundreds of different species of trees in North America. Second, the wood of many species looks very similar, if not identical."
"Identifying wood is not easy for a number of reasons. First, there are hundreds of different species of trees in North America. Second, the wood of many species looks very similar, if not identical."
It depends on the purpose and grade of the lumber.
I have worked an "exotic" lumber dealer that can definitely offer different species and grades of wood from all over the world -- including CITES (endangered species list) lumber with the proper certificates. But their customers are typically woodworkers that want a specific species for a specific look. So it's usually cabinet and furniture makers etc.
I have also worked at a "discount" industrial lumber distributer. They are selling wood to be made into pallets or used at a construction site for bracing. In those cases, the hardwood species are a lot less important. The customer just needs something much stronger than the standard SPF.
It's a fascinating industry. I learned a lot working that job -- even tho I was just implement their ERP systems.
I have worked an "exotic" lumber dealer that can definitely offer different species and grades of wood from all over the world -- including CITES (endangered species list) lumber with the proper certificates. But their customers are typically woodworkers that want a specific species for a specific look. So it's usually cabinet and furniture makers etc.
I have also worked at a "discount" industrial lumber distributer. They are selling wood to be made into pallets or used at a construction site for bracing. In those cases, the hardwood species are a lot less important. The customer just needs something much stronger than the standard SPF.
It's a fascinating industry. I learned a lot working that job -- even tho I was just implement their ERP systems.
I am guessing any unidentified utility hardwood is likely to be poplar. Next guess would be red oak, though in my experience that is usually identified and it costs a bit more. And it comes in less utility sizes than poplar.
It's really a mix. Usually they get mixed in as "utility" hardwood because those pieces don't make appearance grade.
I have seen cords of walnut and cherry mixed in a bundle of utility hardwood before. They just didn't look good for making a cabinetry set or a end-table.
I feel like many parts of CT are already like this, random trees all over the place.
I’m not surprised by Osage Orange. There is a reason it is prized by bow (as in archery) makers.
Too bad they couldn’t do Yew too. That is another top bow wood.
Too bad they couldn’t do Yew too. That is another top bow wood.
For anyone who doesn't know or look this up, Osage Oranges are what we in the Midwest called 'hedge apples', those creepy alien looking green balls you'd see littered in yards.
You mean monkey brains?
This guy calculates a "bow index", and reckons European Yew and Osage Orange are in a dead heat:
https://www.wood-database.com/wood-articles/bow-woods/
But in the comments, someone identifies "speed of cast" aka "self-fling speed" (!) as the key metric for bow woods, and he doesn't have European Yew, but according to that, Pacific Yew and Osage Orange are also pretty much the same!
https://www.wood-database.com/wood-articles/bow-woods/
But in the comments, someone identifies "speed of cast" aka "self-fling speed" (!) as the key metric for bow woods, and he doesn't have European Yew, but according to that, Pacific Yew and Osage Orange are also pretty much the same!
If you really want to get deep into the topic of wood choice for self-bows, The Traditional Bowyer's Bible series is a classic.
After watching this, I made the connection that the French "Bois d'arc" for Osage Orange refers to its use in bows. It turns out that Osage Orange really is one of the best woods for bows.
If you watch the linked video, six mins in he has a “bow score” based on strength and flex. Osage Orange was 2nd, after Dogwood.
Relevant article from Texas Monthly regarding the history of Osage Orange:
https://www.texasmonthly.com/being-texan/osage-orange-histor...
https://www.texasmonthly.com/being-texan/osage-orange-histor...
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Funny that he didn't record the moisture content. Wood that's been properly seasoned gets both denser and stronger. If the pieces here didn't have the same moisture content they could be up to 50% off in terms of strength. Different uses of wood also require different moisture levels, at different times of their processing.
Came here for the moisture question. It would be an interesting dimension to his experiment. Note you can get a moisture tester at the box store for about $20; not a bad thing to have around if you do carpentry, burn wood, or have water problems in your house.
For anyone who found this video satisfying, you may enjoy "Structures : Or Why Things Don't Fall Down" by Gordon.
This plus one thousand. Great book. "The new science of strong materials" is also good. (By the same author)
"Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands."
A favorite quote from these types of engineering analyses.
A favorite quote from these types of engineering analyses.
Haha, so true. Structures can have multiples of strength for safety margins. Airplanes have 50%. Spacecraft - 10%. There's no way anyone is going to design spacecraft parts without being very good at math.
“furniture designers, incredibly, are not taught during their formal training how to calculate the deflection in an ordinary bookshelf when it is loaded with books,”
― J.E. Gordon, Structures: Or Why Things Don't Fall Down
I wonder how the "wood" 3D filament which is particles embedded in a brown PLA would compare. PLA is generally quite weak, this filament is only suitable for ornamental things.
https://all3dp.com/2/wood-filament-for-a-3d-printer-explaine...
For the actual woods, I am not suprised by the ironwood. I once had a coffee table with an ironwood top and it was ridiculously dense and strong.
also, did you know there's an ironwood smuggling problem internationally?
https://www.google.com/search?client=firefox-b-d&q=ironwood+...
https://all3dp.com/2/wood-filament-for-a-3d-printer-explaine...
For the actual woods, I am not suprised by the ironwood. I once had a coffee table with an ironwood top and it was ridiculously dense and strong.
also, did you know there's an ironwood smuggling problem internationally?
https://www.google.com/search?client=firefox-b-d&q=ironwood+...
I would guess that much like MDF, PLA wood's strength is determined by the binding agent. My understanding of this product is that it's basically sawdust + PLA, whereas a wood's strength is stemmed (sorry!!) from its grain.
PLA is not "quite weak". In fact, PLA's tensile strength is the highest of the easily printed materials (so excluding nylon and polycarbonate). Typical printed tensile strength of PLA is 40-60% higher than PETG, for example.
PLA is also stiff, among the stiffest of common printing materials.
PLA is also stiff, among the stiffest of common printing materials.
Yeah, PLA, if you anneal it and use the right grade, has a strength to weight ratio the same as common Aluminum 3003 alloy, about 50MPa/(g/cc), which is also about the same as standard strength steel.
It is quite strong for its weight.
https://www.mmscience.eu/journal/issues/november-2020/articl...
It is quite strong for its weight.
https://www.mmscience.eu/journal/issues/november-2020/articl...
I do not have any experience using pla in an industrial setting. When talking about 1.75mm filament one can buy on a roll for a basic 3d printer, I can say I've printed a number of PLA things at 200-215C with appropriate slicer settings, speeds and such for beautiful looking output results, but all of them can be easily snapped in half by hand if I try.
Many aluminum objects can be easily broken by hand too. The design of your object will greatly affect whether it can withstand a given force.
I have prints that have seen hundreds of pounds of force in use with no problem -- printed on $200 printers with $18 filament.
As a general rule, you will get best results if your part is printed so that the force this in line with the layers, not perpendicular to them.
I have prints that have seen hundreds of pounds of force in use with no problem -- printed on $200 printers with $18 filament.
As a general rule, you will get best results if your part is printed so that the force this in line with the layers, not perpendicular to them.
PLA in the context of low
cost consumer fused deposition 3d printers is quite weak, compared to other filaments that can work in the same printer, such as abs.
For something like a $300 printer you generally have a choice of pla, something like sainsmart tpu for semi flexible, and abs if you can print with ventilation.
https://youtu.be/ycGDR752fT0
For something like a $300 printer you generally have a choice of pla, something like sainsmart tpu for semi flexible, and abs if you can print with ventilation.
https://youtu.be/ycGDR752fT0
I can confirm from trying to cut fallen ironwood trees that they are ridiculously hard. It's viscerally obvious when it takes several times the amount of time and effort with a quality chainsaw.
I was always confused after that experience why there isn't more ironwood furniture, and just assumed it's because it's too difficult to work with.
I was always confused after that experience why there isn't more ironwood furniture, and just assumed it's because it's too difficult to work with.
This is really fun - but isn't information about the janka of most species already fairly accessible online? [1].
I always assumed there was a slight degree of strength variance due to age, humidity of growth region, etc - but maybe having your own tester might come in handy for certain structural engineering cases where accuracy is crucial.
[1] https://www.wood-database.com/wood-articles/janka-hardness/
I always assumed there was a slight degree of strength variance due to age, humidity of growth region, etc - but maybe having your own tester might come in handy for certain structural engineering cases where accuracy is crucial.
[1] https://www.wood-database.com/wood-articles/janka-hardness/
I haven't checked, but I would assume the janka hardness of wood is not super tightly correlated with yield strength. I would expect a variation of 2x for a the janka hardness : strength ratio; some wood would be twice as strong or half as strong as you might expect from the hardness.
So cool to see Matthias here on HN. He has a ton of other articles and videos where he tests different things like this. I encourage you guys to check him out if you haven't.
Matthias is one of the most inspiring engineers I've come across
Matthias is such an inspiration. A true hacker, I'd say.
I remember that he was recently trying to get hired at a tech company. (He was doing something like an Arduino auto-targeting Nerf gun as a portfolio piece.) Did someone nab him?
I remember the days when YouTube videos were automatically flagged as "shallow" by the HN code!
I remember the days when YouTube videos were automatically flagged as "shallow" by the HN code!
What is or was HN code?
The software that implements the site and its functionality. It is, as far as I know, not open.
It was ported to Arc, which is a Lisp variant written by pg.
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I would have liked to have seen Ipe wood tested. It is nearly twice the density as Red Oak, incredibly hard, and actually has a fire rating in the same category as concrete. https://www.wood-database.com/ipe/
For weight constrained beam applications, both bending and compression failures are bending related (tension isn't).
Since bending strength is proportional to the cube of thickness of a beam, wouldn't less dense materials in practice always win out since you can make the beam thicker?
Ie the characteristic metric for beams would be stiffness / density^3
Since bending strength is proportional to the cube of thickness of a beam, wouldn't less dense materials in practice always win out since you can make the beam thicker?
Ie the characteristic metric for beams would be stiffness / density^3
Typically the beam has to fit where it needs to go. A lighter beam doesn’t mean you have room for a bigger one.
That qualification of weight constraint. Brick pillars have sufficient compressive strength to hold fantastic weight, steel or stone as much if not more so (the structural rigidity of the bricks will largely depend on the mortar and skill of laying the courses) so I think this is a peculiar niche to be in. Church roofs use heavy trusses, the compression load is a big part of building strength in flying buttresses and arches.
You don’t need buttresses for trusses. A regular horizontal masonry wall will hold and transfer horizontal load just fine. Buttresses are for supporting lateral loads, created by the arches. Brick walls are bad at resisting lateral walls, which makes them them tip over, hence the buttress. Big wood trusses are more recent invention than arches, and they allowed to do away with buttresses.
Good points but the key observation is to weight: wooden beam weight is not often a significant factor in the design of wooden truss roofs, compared to the strength.
Is gluelam lighter?
Is gluelam lighter?
Doesn't the orientation and placement of the cut for each piece of wood have a huge impact on strength? If you've got a quarter sawn piece from heartwood you're going to get very different mechanical properties than plane or rift sawn sapwood. This and the orientation of the pieces in the tester doesn't seem to have made it into the post or the data sheet.
From the pictures and by conventions of woodworking, these samples all seem to have the wood grain aligned to the major axis. They are also free of knots.
It would be interesting to see, at least for a few species, how the placement of cut affects the results.
It would be interesting to see, at least for a few species, how the placement of cut affects the results.
It depresses me that people can name more fictional T.V. characters than they can types of wood. We need to study nature more. Learn about materials.
There are far more fictional TV characters than there are types of wood. I'm a hobbyist woodworker and TV snob but could still many more characters than woods.
It's wasn't my best metaphor.
Regardless you are correct.
I often wonder what society would be like if we treated engineers and scientists like we do sports and entertainment and what you said I think falls loosely to into that realm of thinking.
I often wonder what society would be like if we treated engineers and scientists like we do sports and entertainment and what you said I think falls loosely to into that realm of thinking.
https://theinfosphere.org/Transcript:Crimes_of_the_Hot
Woman #2: [shouting] I love you!
[Scene: Outside Conference Centre. Scientists from all over the world arrive. Photographers take photos of them and fans in the crowd wave papers for them to sign.]
Woman #2: [shouting] I love you!
[Farnsworth steps out of a limo. Joan Rivers' Head is commentating at the star-studded event.]
The very much sought-after and difficult to get wood in my area is Japanese cypress. Now I'm curious how it would fair in the ranking.
Better ping Toady One and get him to add this info to Dwarf Fortress.
I respect all wood
https://youtu.be/NTL30rkRYPo
https://youtu.be/NTL30rkRYPo
Around Seattle, madrona trees are indigenous. They are very strong, and are preferred to hold hills in place. There's one on my property that is gigantic and leaning at a 30 degree angle. It's been that way forever. It must be fantastically strong to hold that weight through storm after storm.
I wonder how they compare.
I wonder how they compare.
I think a tree holding a hill in place is more a factor of soil, root structure & precipitation than the wood strength. Shallow roots, loose soil: not gonna hold much. Deep roots, compacted or rocky soil: basically reinforced concrete. Whether it's more dry or waterlogged probably changes it too. Also, if the tree grew slanted, it would actually be unusually strong in that position compared to a tree that was shifted into that position.
I was told by many workers that cutting a madrona would dull your saw in short order.
Without reading the article (gotta be honest), Ipe should rate highly if they test it. It is very dense. Heavier than water, it sinks.
Hey I was thinking about ipe too. Bugproof, toxic dust and smoke. Heavy as heck. So hard you break bits, dull blades. Beautiful color and grain. Looks like walnut. Got a piece in my lap right now.
Australian hardwoods are a bit like this. Jarrah looks amazing, is crazy heavy and sinks. New Zealand power poles are still sometimes Jarrah.
Another odd one is old olive. I’ve had sections that when hit with an axe won’t split and bounce the axe. And seemingly remain unmarked. Splitting gnarled olive is miserable.
Another odd one is old olive. I’ve had sections that when hit with an axe won’t split and bounce the axe. And seemingly remain unmarked. Splitting gnarled olive is miserable.
Quoting Kilgour's "Origins of Coordinate Searching" at https://books.google.se/books?hl=sv&lr=&id=4crkFsx73msC&oi=f... .
> In 1936, S. H. Clarke, of Britain’s Forest Products Research Laboratory at Princes Risborough, published a brief note in Nature reporting on an unexpected observation: Detection of relations of ‘‘recorded features’’ on edge notched punched cards with a particular feature already sorted.
> He had sorted a file of several hundred cards each listing a specimen of timber, by increases in specific gravity, and noticed ‘‘by glancing at the arrangement of the other notches . . . a distinct tendency for strength to increase with specific gravity’’ (Clarke, 1936, p. 535). He added that it was easy to recognize unusual correlations among notches.
The spreadsheet plot in this video is essentially the same as the image in the 1936 Nature publication!