Reprint from: Woodwork Joints by William FairhamFox wedging is a technique where the end of a tenon is split and a wedge is inserted, before fitting said tenon into a blind-mortise (a through-mortise can be wedged from the outside). As the piece is hammered home the wedge bottoms out in the mortise forcing the tenon to spread and wedge in the mortise. It makes for a very strong joint.
I was recently converting an old damaged-beyond-repair thumback style Windsor chair into firewood and stumbled upon the chairmakers version of the fox wedged tenon. The blind mortises in the chair seat have been drilled with a chairmakers spoon bit, which results in a round-bottom hole. The bottom of the chair-back spindle has been turned to resemble the hole, split and outfitted with a wedge, which will expand the tenon to completely fill the hole when the spindle is hammered home. Very clever and sly...as a fox.
Above you can see the wedge in the right spindle hole.
