My client had a tabletop, provided a set of turned legs, and I made the skirt.
3″ X 4-3/4″ kerf-mount corner bracket, set of 4. Make sure to get the kerf-mount type, which are much stronger than brackets that are attached only with screws.
Attach the kerf brackets to the apron with # 12 or # 14 x 3/4-inch flat wood screws
5/16″ -18 x 3″ hanger bolts, 8 pack One end of the bolt screws into the legs, and the other end goes through the metal bracket.
5/16-18 zinc-coated hex nuts for attaching the hanger bolts.
Another way to allow for expansion and contraction when attaching the table top is to cut a slot in the skirt and use table top fasteners