[mauvehaus]

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.

[tptacek]

Fun chair force article: https://www.woodreview.com.au/how-to/the-logic-of-chair-desi...

[jnsaff2]

Fun chair anatomy video by arguably one of the most talented ones currently active.

https://www.youtube.com/watch?v=T2g6kGl66XU

[aidenn0]

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]

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.

[kabes]

I know a miter joint, a box joint and dowel joint. But what is a mitered box joint with dowels?

[novaleaf]

could you post the link? I'd love to watch :D

[sgdesign]

https://www.youtube.com/channel/UCJNY2_y5nPoghlAO6FPxHfg

[rfrey]

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.

[fian]

You are probably thinking of dowels used as loose tenons, where a blind hole is drilled into the mating pieces of wood and the dowel is not visible once the joint is together.

Sometimes people glue a butt or mitre joint, then once the glue has set, drill a through hole for a through dowel from an outside face of the joint.

The blind holes approach is tricky to get perfect alignment on where dowels are being added across a longer length. As a hobbyist I've tried a few cheaper dowelling jigs and had mixed success. This challenge lead to other loose tenon solutions like biscuits or dominos which allow for some side to side misalignment while retaining the ability to keep the visible faces aligned.

The through dowel approach avoids the misalignment problem, but comes with the visibility of the end grain of the dowel on one exposed face. Some people are ok with that.

Dowels are still one of the "strongest" options for end-grain to long-grain joints. Many professional woodworkers now favour dominos simply due to who quick it allows them to work and the additional allowance for some side-to-side alignment.

[aidenn0]

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]

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]

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]

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.

[jeffffff]

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.

[Tossrock]

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.

[bradly]

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.

[montgomery_r]

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]

In my experience, the cost has significantly dropped, it's just that back then they were even more absurdly ridiculous

[WillAdams]

If you're making a bed, consider that this is a problem people have worked on for a very long time and there is an entire vertical industry on it.

One reputable company has an entire section in their catalog on it:

https://www.leevalley.com/en-us/shop/hardware/bed-hardware

[WhatsTheBigIdea]

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]

> 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.

[WhatsTheBigIdea]

Agree that you "can't expect the glue to deal with the forces"

A good craftsman would not choose a joint that would see such high stresses.

Additionally if the glue is chosen and applied properly, the wood that the glue adheres to should fail long before the glue.

That said, glue is not as simple as it may seem. There are many different types and proper surface prep and application makes a huge difference to ultimate strength.

For example, many people will mix 2 part epoxy until it "looks mixed" which for a clear epoxy happens pretty quickly. In truth, the resulting bond strength is far more closely related to the amount of mechanical energy that has been transferred into the mixture than the visual uniformity.

Lots of ways to go wrong with glue... but a good craftsman should be well aware of these.

[rfrey]

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]

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.

[btbuildem]

It really does depend on the joint type. Do you expect a lap joint to hold together without any additional fasteners or glue?

[LMMojo]

Yes, the one thing I was missing from all of this is what is the appropriate application for each joint

[klodolph]

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).

[samirillian]

Yeah, intuitively I doubt that these will work the way they’re supposed to because well you’re trying to reinvent the joint. It’s true that the tools are different but I think there has been a steep decline in general joint know-how, so being able to innovate joints would require catching back up to where we used to be to decide if it’s worth it. Tbf if anyone could do it it would probably be Germany.

[WhatsTheBigIdea]

None of these joints is novel in the slightest. Still, is it awesome to have them so well documented. Additionally, the CNC makes them much much easier to use!

[samirillian]

Really. Show me one single source other than this page that uses a meander key lengthening joint.