Some readers seemed confused by my description of assembling a benchtop with the help of a “loose tenon.”
The expression doesn’t mean that the tenon rattles loose in the mortise. Rather it means that the tenon is not integral to either piece being joined. It is like a Domino or a biscuit. It enters mortises in both pieces.
I drew up two illustrations to show how this works. The drawing at the top illustrates the joint when it is apart. The loose tenon is shown floating between the two components of the benchtop.
The second illustration is an “X-ray” view of the assembled joint with 1/2”-diameter pegs piercing the benchtop pieces and the loose tenon.
“Loose tenons” have many other names, including “slip tenons” or “floating tenons.” All these terms are accepted in woodworking journalism.
Hope this helps.
— Christopher Schwarz