Over time, the hexagonal nuts in my bed frame have loosened. I'd like to tighten them, but the routed access is much too small for a socket head, crescent wrench or even needle-nosed pliers -- not that they would provide enough torque to actually turn the nut:
The opening is ~1-5/8" in both axes.
Has anyone found a good way to tighten nuts in such close quarters?
Note in particular that the bed came without washers as a stand-off, so these particular nuts tighten against the raw oak surface, which was routed with the curve shown.
The other end of the bolt seems to be sealed in the leg of the bed -- here's a photo showing the 1-5/8" bolt recess with what seems to be a decorative end cap glued in place: