Like all other scarf joints, this half lap with table scarf joint gives you the ability to create spans longer than the length of your lumber. Similar to other half lap joints, this one consists of each timber being split longitudinally, except in this one each face has a raised area (the “table”). This creates puzzle pieces that fit securely together and strengthen the joint.
This joint is typically secured with pegs, screws or wedges. It is a good connection to have in your repertoire, since it adds strength and interest to a frame.
for a 6 x 6 how much overlap should there be in joint?
2 feet should cover it. You can always go longer for looks.
Can this joint be used over top of a post?
Yes, it will. It is a better practice to have the scarf joint over a knee brace if possible.