I've had to edit this review. One of the chairs is now unusable, about a year and a half after purchase. The problem is that the swivel is attached to the legs via bolts that thread into reinforced plates. These plates are spot-welded to the horizontal bars atop the legs. I suppose the reason for this is so that the holes in the legs don't need to be drilled very precisely as long as the threaded plates are welded on in the right place,

Now, two of the plates on one of the chairs have broken off. See photo. I think I can fix this by drilling straight through the leg and using a longer nut I can fasten with a bolt on the other side, but the quality here is very disappointing for such a good-looking item.