A hardware system for assembly to form an item, such as an item of furniture. The system includes a tension adjustment device, such as a turnbuckle, which may be threadably engaged with two rods, inserted into two rod inserts located on each of the turnbuckle's two opposite sides. The rods may pass through a series of alternating base material components and spacers therebewteen to form an item's body, the turnbuckle being located, for example, in or near the middle of the two series. The ends of the rods opposite the turnbuckle may be threaded into inserts fixed in an end piece of base material of their respective series. The turnbuckle may be twisted or otherwise adjusted to secure or compress the system. A final assembly may have one or more such series and may give the illusion of a solid bar of hardware being passed through the base material.