It's really a form of threaded insert. There are two kinds: one is meant to sort a bulge about the again aspect in the panel as a screw is tightened in its threads. One other is likewise drawn in employing a screw, but is drawn to the sleeve rather of https://waylongynbn.tinyblogging.com/the-smart-trick-of-fasteners-for-wood-that-no-one-is-discussing-70223191