Bookshelf joints

Question

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

Answer 1

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.

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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.