I have a couple of boards that are parts of a table I am assembling, and I wish to know the name of the metal piece of hardware circled in red, below. I would have thought it was called a bolt, but I cannot find anything like it under the name "bolts" at home depot.
EDIT:
Upon closer inspection, the hardware appears to be threaded inside for accepting a machine screw. This may help with identification, and I believe that one or two of the answers below may be already correct. I am reluctant to remove it from the hole because I do not want to risk stripping the wood in the hole.
Best Answer
While difficult to tell for sure I think it is an E-Z Lok threaded insert. It consists of a course threaded screw that is inserted into the wood. A pilot hole is drilled and the insert is screwed in with a Allen wrench until it is flush. The center of the insert is tapped for a machine screw. The advantage of this fastener is it can be disassembled numerous times with out stripping the wood.