Anyone familiar with this type joint? Looking to build something similar but worried it will be very wobbly.
https://areastore.com/en/products/86375-krisel-estante
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2If you are planning on making one, I suspect there may be dowels inside the legs extending between shelf levels. IF they are large enough and extend several inches into the leg on each side of the shelf they could be strong enough to act as a single piece. Of course all of the lateral movement must be absorbed by the contact of the legs with the shelves so, at best it is not the strongest shelf assembly for dragging with heavy loads.– Ashlar ♦Commented May 31, 2022 at 1:13
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We can't see joint so impossible to advise!– Volfram KCommented May 31, 2022 at 5:07
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1"Anyone familiar with this type joint?" Well there's no established joint here so there's not really going to be anyone familiar with this. My first though was that this is a terrible design for a bookshelf (fine for display items) but based on what we can see the shelves should actually be stiff enough given they're solid wood and have raised lips, which increase stiffness if attached well. But the whole thing would have to be put together with the tightest joints you can imagine (which I bet it isn't) not to very subject to racking.– GraphusCommented May 31, 2022 at 12:35
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1"Looking to build something similar but worried it will be very wobbly" I'd make a substantial wager the one in the link is pretty wobbly! If you just want to build something inspired by this rather than a direct copy, I think you'd have to be quite flexible on the design if you want to make something stable – either increase the dowel thickness considerably (double or more) or add extra wood (some type of cross-bracing) to secure against racking. The commercial one is made from acacia, what species were you thinking of using for your version?– GraphusCommented May 31, 2022 at 12:37
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If I were to do this I'd use threaded inserts and threaded rod, and the dowels would only appear to be through-holes. Instead, they'd be large wooden "bolts" holding the whole thing together. And it will rack eventually.– user5572Commented May 31, 2022 at 21:25
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1 Answer
Note: all of what follows assumes this will be used to hold a fairly normal number of books, which requires fairly significant weight holding even assuming paperback, see previous Answer. If yours is intended for display items the strength requirements tend to be far lower, and in fact some 'semi-decorative' shelf units are not particularly strong/stable but work well enough for their intended purpose because of the light loads.
Anyone familiar with this type joint?
There are a few different ways this basic design could be implemented as the Comments illustrate. There's no way of knowing how this shelving unit is actually constructed without examining it, or finding an assembly diagram or something similar if one exists.
Looking to build something similar but worried it will be very wobbly.
As I say above, I have a strong suspicion the commercial one is wobbly, given the diameter of the dowel 'legs', unless the fit of the dowels in drilled holes in the shelves is particularly tight, and the design allows them to be drawn together firmly1.
You most certainly wouldn't want to drag one of these across the floor when fully loaded O_O
Personally if I were building something similar I would prefer to go up a lot in the diameter of the dowel, possibly as much as doubling them, although I'm aware that this significantly alters the aesthetics of the piece2.
Since very thick dowels in the species you wish to use may be commercially unobtainable you may need to think about creating them yourself. Obviously a lathe is the first choice here but if you don't have one you don't have one. Luckily there are numerous guides online to creating fat dowels using other power tools — chiefly the router (in a table, with a suitable bit) but also the table saw (using a custom sled). It's also quite easy to envisage an efficient way to make dowels on a bandsaw, again with a sled of some sort.
You can produce round stock by hand using standard planes and then scraping and/or sanding to complete. The method is a lot of work but can create surprisingly perfect cylinders with care and attention, so I wouldn't dismiss the option completely if this is the method of last resort in your case.
Don't forget the shelves
For a self-built version don't overlook the shelves themselves as part of the strength of the structure. Material matters. This project would not be a good candidate for plywood unless you scale the piece down, or double up the ply to make substantially thicker shelves (assuming use as a bookshelf).
The original is stated as being made from acacia, which is a stiff hardwood, so if planning on closely matching the shelves of the original you'll want to use a similarly stiff hardwood (red oak or better) or softwood (Doug fir). But if you're OK with going thicker this widens the choice of possible species significantly, to the point where you might reasonably include other softwoods — but note that if you want matching dowels they would need to be much thicker to be equivalent strength.
1 For example metal screw connectors are hidden within the dowels, although the joint to the top shelf remains questionable.
2 Possibly enough to actually spoil the looks so much that its appeal is lost.
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I don't think there is anything you could do with that design that would prevent racking in the long run, if it's loaded with books. Well, maybe one thing - if the posts are firmly screwed to the shelves and each other, you could pack the entire shelf with books tight up against the posts. That'd be pretty stable ;-) Commented Jun 3, 2022 at 1:47
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@WalnutClose, yes racking in the long run is definitely a concern, I guess it's the first thing that most woodworkers would think of. I mainly put in an Answer so that this wouldn't be one of those Qs that didn't go unanswered and resurfaced periodically forever.– GraphusCommented Jun 3, 2022 at 17:08