[HN Gopher] Digital Wood Joints
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Digital Wood Joints
Author : montgomery_r
Score : 101 points
Date : 2024-04-25 13:46 UTC (9 hours ago)
(HTM) web link (openup.design)
(TXT) w3m dump (openup.design)
| uticus wrote:
| the images are great, but need more info about strengths &
| weaknesses of each type
| geekodour wrote:
| think the site suffered a hug, not opening for me ;(
| WillAdams wrote:
| I believe it's the same as:
|
| http://winterdienst.info/50-digital-wood-joints-by-jochen-gr...
|
| (which is the original site and which would be better to
| use/link to)
| 8ig8 wrote:
| Charles Hayward [1] has a great book on the topic:
|
| Woodwork Joints
| https://archive.org/details/woodworkjointski0000hayw_k7x4
|
| Hayward discusses not only the joints, but techniques for cutting
| them with hand tools.
|
| There are plenty of used copies out there. Hayward has many other
| useful books.
|
| 1: https://en.wikipedia.org/wiki/Charles_H._Hayward
| lemma_peculiar wrote:
| this is an excellent reference - not only for computer-controlled
| wood processing, but also for digital fabrication. When trying to
| create pieces made of plastics, you will sometimes need a strong
| joint, and wood-working is the perfect place to look
| jefb wrote:
| Very cool graphic. However emphasizing the juxtaposition between
| pictures of wood joints on the internet and actual real-life wood
| joints with the phrase "digital" is a bit perplexing.
| e28eta wrote:
| I think "digital wood joints" emphasizes that they're meant to
| be cut with a CNC, and thus aren't the traditional wood joints
| that have been taught for centuries. I don't think it has
| anything to do with the fact that this content is available
| digitally.
| michaelt wrote:
| Honestly I thought they were trying to make a cute pun by
| calling finger joints 'digital'
|
| Your interpretation is more likely, though. And explains why
| so many of the joints are weird and look like they'd leave
| gaps...
| affgrff2 wrote:
| Offenbach also hosts a relatively large Japan festival (in
| Germany). Wood joinery, at least in my mind, is a very Japanese
| craft. I wonder if this is by accident.
| mauvehaus wrote:
| There are a couple of Japanese joinery books out there. One
| that I've read gives the reasoning for all of the joints in the
| Japanese tradition for joining two boards end to end (thereby
| creating a longer board, in effect) is that the timber
| available for building in Japan doesn't come in long, straight
| lengths.
|
| I can't tell you if that's true or not, but I have a hard time
| seeing folks putting so much work into developing such joints
| without a pressing need for them.
| jcl wrote:
| There's a wonderful little carpentry museum in Kobe, highly
| recommended:
|
| https://www.dougukan.jp/exhibition?lang=en
|
| It focuses a lot on the evolution of precise woodworking tools,
| like saws and planes. They also had examples of complex joints,
| made without nails or glue.
| montgomery_r wrote:
| Lovely!
| mauvehaus wrote:
| These are all designed for CNC cutting, and appear to be intended
| as one-sided jobs worked with the face of the board down. That is
| generally the simplest way to hold a board on a CNC.
|
| I would caution anyone thinking of doing joinery this way to
| consider whether it's actually suitable for the application. I
| was at a coffee shop once where absolutely every chair in the
| place was starting to fall apart. The reason was that the joinery
| was all some variation of half-lap, which doesn't constrain the
| movement of the pieces in all of the directions that matter. Once
| the glue failed, the chairs started coming apart.
|
| I would also add that the corner joints meant to replace
| dovetails or a box/beehive joint are unsightly with all the
| required dogboning and will not improve aesthetically with the
| addition of glue. I would further point out that there are
| already quick ways to cut dovetails or box joints with a router
| quickly and efficiently. It would be hard to convince me that
| there's a truly useful role for cutting an uglier version of a
| box joint on a CNC.
|
| Source: am a furniture maker who does some CNC work.
| e28eta wrote:
| I wonder how much of the simplicity is due to the fact it was
| created in 2004. I don't have a good feeling for how quickly
| things progressed over the last 20 years
| mauvehaus wrote:
| I wasn't in the trade in 2004, so some of this is a bit
| speculative:
|
| It looks like everything on the poster is made to be cut on a
| 3-axis machine. Stepping up to five-axis is a huge leap in
| cost at present, and surely was then as well.
|
| Tooling has likely improved in availability and cost since
| 2004 as well. Automatic tool changers have probably also
| become more affordable, but just like going to five-axis,
| you're getting into a whole different class of machine once
| you start talking about adding that.
|
| Some of the reasons to cut stuff single-sided on the flat are
| unchanged by any of that though. It still costs you precision
| (and time) to flip a workpiece over, and you're going to have
| issues if you don't have good consistency with your material
| thickness if you need to reference your Z axis to the
| material surface rather than the bed surface.
|
| Working an end of a long piece remains a pain in the ass for
| fixturing that involves a hole in your machine bed, and
| possibly the floor as well. Tenoning a bed rail, for
| instance, is inconvenient however you do it.
|
| All of my CNC experience is on a three-axis machine, five-
| axis gets you a lot of flexibility that most places won't
| have unless CNC work is their primary focus, or at least core
| to their workflow. I've seen a shop that builds high-end
| windows with a large five axis machine. I have no concerns
| about the durability of their products, it's just that most
| people don't have access to that kind of capability.
| montgomery_r wrote:
| Thanks for the informed commentary. I'm surprised that the
| tools haven't dropped in price faster, but perhaps there is
| a de minimis based on amount of material / strength /
| precision engineering required. I got to the site because I
| have a plan to make a bed frame (poor first project choice
| I know) and found this whilst looking for joints that might
| work gluelessly.
| wizardwes wrote:
| In my experience, the cost has significantly dropped,
| it's just that back then they were even more absurdly
| ridiculous
| jeffffff wrote:
| i'm a hobbyist woodworker with more money than time. i have
| a pretty basic 3-axis cnc and i thought it would save me
| time, but it really doesn't. the only thing i actually use
| it for is cutting out router templates, and even that would
| be done better with a laser cutter (although a good laser
| cutter costs a lot more than my cnc).
|
| i could see how a machine big enough for 4x8 sheets with an
| automatic tool changer, a vacuum table, and all the
| automatic calibration gizmos might be a time saver for a
| production shop, but if you're building something that's a
| one-off or you don't have all the setup automation goodies
| (which are $$$$$) then setup and programming usually end up
| taking longer than doing the work the old fashioned way.
|
| for tenon cutting like in the bed rail example you gave, i
| have a hard time imagining any situation where cnc is going
| to be more efficient than a domino xl.
| bradly wrote:
| 4x8 CNCs with a vacuum table really aren't faster. Even
| the watercooled CNCs I've used are still too slow for
| joinery. All the furniture shops I've worked in have been
| dominated by the Domino for most joinery tasks.
| Tossrock wrote:
| I find CNC is a time-saver for one-offs when the work is
| complex enough that it'd be difficult-to-impossible to do
| by hand, eg complex curving cuts, engraving/pockets, etc.
|
| I actually saw an unusually straightforward example of
| this last year - a group of friends and I were making
| instances of Tyler Gibson's 1-sheet portable bike rack
| design (it's great, check it out:
| https://www.thetylergibson.com/building-a-better-
| portable-bi... )
|
| One group of two-ish people used jigsaws to manually cut
| the pieces, and I used a Shopbot 4'x8' CNC router. Very
| roughly, it took about twice as many man-hours to make
| one by hand, vs by CNC, and the result was less clean.
| CNC could have done even better, but due to warping of
| the sheet, it failed to cut all the way through in
| places, and I had to do a cleanup pass with the jigsaw.
| And once the upfront cost of generating the toolpaths etc
| was paid, it would improve again.
| klodolph wrote:
| Yeah. I want to know how well these joints will last in
| different scenarios and how the tradeoffs are.
|
| I've seen YouTube videos where people test different wood
| joints to see how much load they can withstand, but I assume
| the results will be different if you account for things like
| changes in humidity over time, which causes the wood to expand
| and contract (which doesn't happen isotropically).
| tptacek wrote:
| Fun chair force article: https://www.woodreview.com.au/how-
| to/the-logic-of-chair-desi...
| jnsaff2 wrote:
| Fun chair anatomy video by arguably one of the most talented
| ones currently active.
|
| https://www.youtube.com/watch?v=T2g6kGl66XU
| WhatsTheBigIdea wrote:
| If the glue has failed, there are some serious craftsmanship
| issues regardless of the joint type.
|
| With the exception of the joints labeled "...with key" these
| joints are all very remote from the types of joints used in
| traditional Japaneses temples which do not use glue.
|
| These are mostly western style joints, which are also very
| beautiful and useful, but generally expected to be assembled
| with glue.
|
| Great resource!
| logrot wrote:
| > If the glue has failed, there are some serious
| craftsmanship issues regardless of the joint type.
|
| No. You can't simply use whatever joint you want and expect
| the glue to deal with the (sometimes enormous) forces applied
| to it.
| btbuildem wrote:
| It really does depend on the joint type. Do you expect a
| lap joint to hold together without any additional fasteners
| or glue?
| rfrey wrote:
| This goes against the conventional wisdom that a properly
| glued wood junction is stronger than the wood itself, and
| that under such forces it is the wood that will fail.
| lmm wrote:
| The wood would've failed at the same place if you'd
| carved a whole chair in that shape out of a solid piece
| of wood. The problem is that the design concentrates
| forces at the joint (or the "junction") in a way that no
| material can withstand.
| LMMojo wrote:
| Yes, the one thing I was missing from all of this is what is
| the appropriate application for each joint
| aidenn0 wrote:
| As someone who is _not_ a furniture maker and doesn 't have
| access to a CNC machine, I was surprised by how good of a joint
| I can make with just a doweling jig. It does end up slightly
| more visible (assuming you aren't painting it), but it creates
| a very strong joint that is hard to mess up.
| foobarian wrote:
| As another layperson who always dreamed of making dovetail
| joints for strength, I was quite surprised at various
| explorations of joint strength on Youtube that tend to find
| that mitered box joints with dowels or splines beat most
| other joints by a wide margin. This is great because they are
| even easier to make, and can be made to look quite nice if
| you use a contrasting wood for the dowel/spline.
| rfrey wrote:
| How is it more visible?
|
| Dowel joints are great, as far as I know Krenov never used
| anything else on his cabinet carcasses. I'm not sure why they
| developed a bad reputation.
| aidenn0 wrote:
| Easiest way is to drill through, then cut and sand the
| dowel flush; leaves a round circle where the grain doesn't
| match for each dowel.
| abakker wrote:
| Excellent points all around. As a fellow woodworker / CNC
| person, I will say it often frustrates me how people with CNCs
| demand that the WHOLE process be done on a CNC. 90 degree
| corner chisels exist and make nice interior corners without
| needing dogbones. Other shapes can be trimmed/finished by hand.
| Once the CNC sets up nice reference surfaces and removes all
| the waste it's actually pretty easy to clean up the insides of
| dovetails to sharp corners.
| e28eta wrote:
| Based only on the pics in the "poster", it looks like a lot of
| the joints in the second half have visible gaps. I think I would
| have expected more emphasis on joints that can be cut with the
| CNC's round cutter, but which also come together cleanly.
|
| Also, an over abundance of lengthening / scarf type joints, more
| than the typical woodworker would use, IMO.
| chiffre01 wrote:
| I'd like to think we're at a place where CNC machines are cheap
| and accessible enough that clever tricks or new tools are just
| around the corner to overcome some of the inherent issues of
| making basic wood joints on a CNC router.
|
| To me, these look like a stepping stone to something better.
| They're all intended to be used with a flat-shaped endmill, and
| all probably have strength and aesthetic issues. One solution is
| using different router bit shapes in combination with traditional
| techniques, but this is more labor-intensive.
| jeffffff wrote:
| we're not really close, for two reasons:
|
| 1) programming takes a long time, and it only makes sense to
| take the time to do it if you're making a bunch of copies of
| something. this is something that could be improved with better
| software and ux - if cad programs made it easy to just drag and
| drop joints from a joint library into your model then this
| would be a different story. a hardware+software solution could
| also work here, something like a cnc version of
| https://www.woodpeck.com/multi-router-group.html where the
| software makes it easy to scale the templates to your work
| piece.
|
| 2) setup takes a long time on the affordable machines. every
| time you change bits you have to recalibrate. positioning the
| work piece on the table and clamping/taping it down takes a lot
| of time. if you have to flip the work piece over then that
| takes even longer and positioning is even more critical, and
| programming is more complicated as well. regardless of whether
| your designs require cutting on one or both sides, you have to
| program tabs into your design so the router doesn't cut all the
| way through (or else the piece will move and the router will
| screw it up), and then you have to go back and cut the pieces
| out the rest of the way manually and trim off the tabs with a
| flush trim router bit. the high end production quality machines
| mitigate a lot of these issues, but now you are talking about a
| machine that costs at least $100,000 and takes up a whole room.
| WillAdams wrote:
| I've been working on the software end of things:
|
| http://tug.org/TUGboat/tb40-2/tb125adams-3d.pdf
|
| and
|
| https://community.carbide3d.com/t/a-different-sort-of-
| box/36...
|
| and for more see:
|
| https://willadams.gitbook.io/design-into-3d/programming
| OJFord wrote:
| Meh, Matthias Wandel's still going to beat you on speed (and
| quite possibly strength) with his homemade pantorouter or box
| joint jig.
|
| As much as I like nice joint design, I think a lot of that
| aesthetic beauty comes from when it's not machinable (or not
| traditionally anyway, iirc the pantorouter can make some pretty
| tight dovetails - because of the orientation vs. trying to route
| them 'normally'). It's not how fancy and curvey can it look, it's
| how intricate and fine the detail. Chunky dovetails don't look
| better than box joints in my opinion.
| WillAdams wrote:
| I would argue that it shouldn't be necessary to see joinery at
| all --- I find full-blind dovetails far more impressive and
| aesthetically pleasing.
| WillAdams wrote:
| I've been working on this sort of thing for a while.
|
| For a Japanese spin on this see Tsugite:
|
| http://ma-la.com/Tsugite_UIST20.pdf
|
| which I worked through at:
|
| https://community.carbide3d.com/t/a-study-of-joinery/28492
|
| Traditional joints (box, dovetails, or obscure variations such as
| Knapp (cove and pin)) require a vertical fixture and 3 setups (at
| a minimum) --- cut parts to length and machine internal features,
| mount four board and cut joints in 2 corners, flip boards (with
| correct orientation) and cut other two corners.
|
| Rabbet joints are simpler --- so simple that they were covered in
| a video as "The Simple Box":
|
| https://www.youtube.com/watch?v=V93xDM3lXsM
|
| (ob. discl., I work for Carbide 3D)
|
| There have been a number of programs developed for joinery. A
| current commercial option is:
|
| http://www.g-forcecnc.com/jointcam.html
|
| (but it requires a vertical fixture)
|
| One commercial option became freely available:
|
| https://fabrikisto.com/tailmaker-software/
|
| and ingeniously has an option where a 30 degree V endmill is
| used, but to cut boards held at a 15 degree angle, affording a 90
| degree cut with a great deal of control and flexibility --- this
| can multiply setups to 9.
|
| A variation I've been experimenting with is full-blind box
| joints:
|
| https://community.carbide3d.com/t/full-blind-box-joints-in-c...
|
| They're reasonably easily drawn up, though they do have some
| rather specific tooling requirements (a narrow 90 degree V
| endmill, a square tool of that or smaller diameter, and to make
| things easier, a large V endmill)
|
| One test project was so tight that after putting it together for
| a dry-fit before gluing I was unable to get it apart:
|
| https://cutrocket.com/p/63781eaf9822f/
|
| I've been working on a programming system to make this sort of
| thing a bit easier:
|
| https://github.com/WillAdams/gcodepreview
|
| and have some sketched out joints which I've not been able to
| make using existing CAM tools which I hope I'll be able to do
| using this system (if anyone could recommend books on conic
| sections, I'd be grateful --- that's where I got bogged down last
| time).
| KaiserPro wrote:
| I wish I could find the clip now, but with the advent of
| practical router bits with pantographs, there was a fashion in
| the late 1800s to replace dovetail joints with dowel and C type
| joints. They were really hard to make fast by hand, but easy to
| do with machines.
|
| They could be made to higher tolerances, and had more surface
| area, and I assume were more reliable to make/hold draws
| together.
|
| These are very similar to the idea here.
|
| EDIT: thankyou to mikey_p and WillAdams who pointed out the joint
| I was looking for was the Knapp Joint:
| https://www.finewoodworking.com/2018/09/26/history-cove-pin-...
| WillAdams wrote:
| Probably you were thinking of "Knapp joints" (cove and pin)
| which had a currency of a decade or so (their presence is used
| to date furniture), but which were replaced by machine cut
| dovetails.
|
| A CNC router affords a lot of new possibilities, e.g., this box
| which has an integrated lid:
|
| https://community.carbide3d.com/t/as-funny-as-a-3-dollar-box...
| mikey_p wrote:
| You're thinking of the Knapp joint which were sometimes called
| dovetails. The pantograph router version is a modern recreation
| of how the original was made.
|
| This video has some explanation of the new method and why they
| were originally popular in the first place (mostly limitations
| of available machines):
| https://www.youtube.com/watch?v=MlJjsvph3r8&ab_channel=Matth...
| KaiserPro wrote:
| Excellent thank you for the video!
| Animats wrote:
| Nice. But the link is to a clickbait site with dark patterns for
| the privacy policy. The real article is here.[1]
|
| Somebody should run these through a finite-element package to
| compute their strength. Some of those look fragile.
|
| [1] http://winterdienst.info/50-digital-wood-joints-by-jochen-
| gr...
| btbuildem wrote:
| Precisely! They look pretty but there's a reason (beyond tools
| and skills) some of these have never been seen in practice.
| Would be super interesting to see stress analysis on these.
| Duanemclemore wrote:
| This is phenomenal. I wish I had it to share with a student I
| worked with last year. Even without this, he came to similar
| realizations and explored similar territory with significant
| results.[0] He began by comparing and contrasting traditional
| Japanese joinery with CNC milled joints. He realized that the
| critical difference was that Japanese carpentry joints are almost
| always entirely squared off (due to the flat saw and chisels).
| Yet the inside corners created with CNC were always rounded. So
| he let this critical difference be the animating concept of the
| project.
|
| So if you enjoy this, you might enjoy Luke's work too!
|
| [0]https://issuu.com/lukemurrayarc/docs/portfolio_2023 starting
| at page 26-27.
| stcredzero wrote:
| Here is what immediately comes to my mind. -
| Figure out a way to parameterize joints - Create an
| automated evaluator that uses finite element analysis -
| Evolve joints with a genetic algorithm
| btbuildem wrote:
| Interesting idea, using the strengths of the tooling to expand
| how joinery can look. Some of these are photos; looks like they
| made actual wood examples of some of these joints.
|
| What is really missing for me here is complete pieces, utilizing
| some or many of these new joints throughout. Are they practical?
| Do they look good as part of a larger whole? Even 3D renders
| would be a good start, if not an actual physical piece.
| netsharc wrote:
| Off-topic, but that's a giant fuck you of a cookie popup... it's
| got 3 options of "high/medium/custom data privacy", a duration of
| how long I would like to keep those settings (just like those
| nagware popups of "Try OneDrive/Teams/[whatever fucking bullshit]
| now!" with no option for "Get off my OS!", only "Remind me
| later"), a customize toggler that makes it even larger to have
| more settings. Someone programmed this to frustrate the user with
| "
|
| And the description for the 3 options is contradictory. Above
| them it says, "Select a Data Access Level", but selecting "High",
| the description is "Highest level of privacy"... So what does it
| do, give the advertisers a high level of access, or give me a
| high level of privacy?
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