Thoughtful planning and careful workmanship in constructing the case that will house the drawers will pay off later. The web frame construction in this solid wood design, only one of many ways to create a drawer case, will serve to illustrate some key principles. In this project, each runner is set in a dado in the vertical partition which forms the side of the drawer housing. A tenon at the front of each runner is glued into a mortise in the front divider. The runner is screwed to the partition near the front and is slot-screwed near its back end. The rear end of the runner has a tenon which is fitted without glue into a mortise in the back divider. This arrangement allows the case sides to move unrestrictedly with seasonal moisture content changes.
Whatever the form of case construction there are some important points to monitor. The width of the drawer housing should slightly widen toward the back of the case. This allows the drawer to be pushed in and pulled out smoothly without binding. Ideally, as the drawer is pulled out almost to its limit, the sides will gently tighten against the housing. It is futile to measure this tiny widening with a tape or rule. Instead, cut a piece of scrap or use a pinch rod setting so it just fits the width (or gently binds) at the front of the housing. Then slide it toward the back where you want it to “release” and slide freely. The clearance is perhaps 1/64 inch; I don’t measure it. At least ensure that the housing does not narrow toward the back.
In the photos below, getting a bit ahead of ourselves here, I’m showing how a fitted drawer front laid flat is snug against the sides at the front but has clearance at the rear of the case. (Fitting the front is covered later in the series.)
It is easier than it might seem to achieve this sort of tolerance. For this project, I cut the joints, then dry fitted the vertical partitions and performed the testing process as described above. Then I disassembled the case and simply hand planed away some thickness on the inside surfaces of the partitions according to the indications of the testing. I reassembled the case and retested. After the case refinement was completed, I ran the dadoes and constructed the web frames.
A few more things require attention. The surface on which the drawer rides should be free of twist. This is mainly controlled by cutting the dadoes for the runners symmetrically in each partition. The front to back consistency of the height of the housing is less important but the height should not decrease toward the back. The front opening ideally should have four 90 degree corners, but don’t worry, small errors can be compensated when sizing the drawer front.
These same general principles can be applied to fitting solid wood drawers into other case designs, such as frame and panel, plywood, and veneered constructions, though the planning steps required to implement them will be different. For this series, I will stay focused on one example of a solid wood project.
Next: how fitting the drawer front is the key step.