Mortise and Tenon jointS as Design feature

Joinery is a skilled approach to combining wooden elements so that the basic unit of lumber, the board or plank, can be combined in a functional and ridged form that is good for something. Joining these pieces has been refined into basic forms that are not simply good engineering, but required for the longevity and durability of what is made. Joining techniques have been so ingrained in our culture (I just love good puns), that it doesn't take an expert to appreciate an ability to join wood in its traditional forms.

In modern construction, these forms have all but disappeared, except as kept alive by architects and builders doing their best to convey a particular feel or style. Manufactured goods generally skirt away from joinery or attempt to mimic it only in appearance because manufacturers no longer can afford to take time to compose each piece, or deal with variation. The techniques of joinery require changing the geometry of the raw material, whereas modern products are generally variants on the shapes that are most easily manufactured. Good joinery is a preservation of a way of thinking in danger of replacement by a perspective of mass production. Historical artifacts are a testament to how durable and beautiful wood furniture can be.

So, after a long philosophical discourse on why I think its important to keep traditional joinery alive, here is how I built a bed frame using the mortise and tenon joint. The mortise and tenon is considered strong for good reason. The cross section of the horizontal member passing through the vertical post is what determines its strength. I cut the mortise with chisels and the tenons with saws and planes. Fit between the two pieces was aided with files. While my methods were somewhat crude and not as perfectly fitted as might be hoped, the joints are still attractive. One way the joints were highlighted was by allowing the tenon to extend slightly through the mortise, so it is both visible and can be felt without protruding far enough to be a knee knocking hazard.

In this piece, there are two mortises adjoining at right angles. I think it would be preferable spacing these apart and leaving material between, but it still came out strong. There were also blind mortises in the upper cap portion of the headboard that are not visible. The headboard and foot board both incorporated this joint in the lower frame area as well as to hold the cap on. Each cap and bottom rail in these was fitted with a blind dado which housed the ends of the ship-lapped planking. Shiplapping was used to prevent problems with shrinkage across the grain. So far, we haven't had any significant issues with this.

Here is the final product. The joints give a distinct look and unify the piece, giving it a solid, but refined look. I just realized I haven't said anything about the hardwood selected for this project. The hardwood we settled on was Khaya mahogany. It isn't known for being as flashy as Sapele, but it still has some fantastic striping.

The mahogany used here was finished with shellac and wax. The natural gold striping is very bold on this piece. Mohogany striping can be very dramatic. It also darkened significantly in a couple of months, so be aware of this when using clear or lightly tinted finishes. One reason mahogany has been so highly prized is because of this characteristic. It's rich brown color comes with age and has been a distinguishing characteristic of long lived and finely crafted work. For this reason, I'm especially glad it could be used on this piece using traditional joinery.

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