Here’s a relatively easy way to glue up the mitered case of the sideboard. In preparation for attaching the sides to the bottom, run a strip of blue 2” painters tape along the underside of miters on the bottom panel. The drawing below shows this step. Split the width of this tape, half on the bottom, half to support the sides. Position the point of the sides against the points of the bottom (make sure they’re flush at the front) and press the tape in place.
To give you plenty of working time hide glue is best to use in this instance. Start by applying glue to the stopped grooves and bottom tongues of vertical dividers. Place the dividers in the grooves and align them flush to the rabbet on the back side. Clamp them in place with clamping squares. Detail ‘a’ shows a shop-made version of a clamping square.
Next, apply glue to the surface of the miters. Then stand the sides up and clamp them in place with clamping squares as well. Now lift the partially assembled case off the surface with two-by blocks and apply more tape perpendicular to the tape holding the miter joint.
Let the glue set before you add the top and leave the case up on the blocks as well. When it’s time to add the top, keep the tape and clamping squares close at hand, you’ll use them there as well. Start by applying glue to the tongues of the dividers and the grooves and miters of the top. When it’s dropped in place, confirm it’s flush to the front before adding the tape, clamping squares, and clamps.
