Sofa Cabinet Framework

A recent project was a sofa cabinet which needed to be 8’ long. For the reasons of the long span, and the hope of it meeting the “hundred year warranty,” uncommon strength was necessary. The angled braces at the bottom give visual support, like the arch of a bridge, but they also stiffen the ends of the lower face frame, and make a wider connection to the leg.

For the best strength, wood joints need physical wood crossover. The traditional mortise and tenon joint is a thing of beauty and enduring function, when perfectly executed. But I chose the underrated dowel for most of the joints, which can imitate or exceed the function of the mortise and tenon in several ways:

  1. The holes in both parts to be joined are made with the same drill, giving the best repeated fit.
  2. Dowels are pre-made with spiral flutes that hold just the right glue thickness and resist being pulled out.

Spiral fluted dowels

Below are two pieces of face frame, with the holes drilled and dowels just glued in. The good fit shows a small amount of glue pressing up and is cleaned off before it sets up. By the way, the knot was not going to show, but it seemed worthy of replacing with a solid plug. Maybe some day when it is moved, it may be noticed on the inside of the bottom face.

For drilling the holes, the best helper tool I have found is the Dowelmax. It is adjusted by adding washers to move the dowels farther from the edge, and I also use spacer sticks like the one shown on top of the walnut leg. This allows very accurate repeat positioning for each part of the process.

By patiently laying out the joints, and positioning the jig carefully in place, very accurate results can be gained. Then, there is the important sequence of gluing, so that all of one face is completed before adding sides. I always dry fit each joint to make sure it goes together as planned.

The last glue up step is the most nerve racking, as the second entire end must be clamped to front and back face pieces. The length of the cabinet required use of two clamps hooked together in a couple of places.