Making Multiple Through-Mortise-and-Tenon Joints


Wedged mortise-and-tenon joints add visual interest to any casework.
By Rob Porcaro
Pages: 62-65

From the August 2008 issue #170
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To join partitions or shelves into solid-wood casework, woodworkers have several options. This basic task of connecting the end-grain edge of one board to the face of a second board can be dispatched with simple nailing, or indulged with precision sliding dovetails. One of the most elegant options is the multiple mortise and tenon.

Woodworkers may shy away from building this joint because it seems complex, even intimidating. The traditional approach to construction involves burying the end of the tenon piece in a fully-housed dado in the mortise piece. I believe this unnecessarily complicates building the joint, leaving almost no margin for error. More important, it creates problems in case construction. I hope to show that adding this joint to your repertoire is doable with much of the same general skill set that you’re already using for making dovetails. Better and easier – now that’s what I like.

I’ll guide you through the construction of a sample joint using two short pieces of 3/4″-thick hardwood about 5 3/8″ wide. The vertical board in the photo below left will be the tenon piece, which will be joined to the face of the mortise piece.

The key to this method is to start with a “giant tenon” with a narrow shoulder. This offers several advantages over a fully housed dado. First, the shoulder will keep the joint line tight and clean, even as the wood seasonally varies in thickness. Second, you can do final smooth planing of the surfaces after you have made a final dry fitting of the joint. Third, it allows you to plane the subtle adjustment of a drawer housing in a case, such as to make the rear of the housing a hint wider than the front. Finally, the shoulder is a handy and reliable registration for shelf or partition length in a case.


From the August 2008 issue #170
Buy this issue now