Dovetail Drawers

ANSI/AWI 0641-2019 tests a drawer in three directions. Its drawer front tension test pulls the front away from the box and requires minimums that rise with the specified Performance Duty Level, from 889.64 newtons, or 200 pounds-force, to 1,779.29 newtons, or 400 pounds-force; the default duty level when none is specified is Duty Level 3. Its drawer bottom compression test requires a minimum of 1,112.06 newtons, 250 pounds-force. And it refers drawer slide load capacity to ANSI/BHMA A156.9, listing general purpose drawers at 34 kilograms, 75 pounds. The Architectural Woodwork Standards add the procedure our joinery guide describes: a ten-pound steel rod rolled thirteen inches into the drawer back three times and into the front three times, with the acceptance criterion that all joinery remain intact.

ANSI/KCMA A161.1, the residential standard, loads a drawer at 15 pounds per square foot and cycles it 25,000 times, requiring it to remain operable with no bottom deflection that interferes, and drops a 3-pound weight 8 inches onto the drawer front assembly ten times, allowing no looseness or damage that impairs operation. It also drops a 3-pound steel ball from 6 inches onto drawer bottoms. Those are pass thresholds for a certified cabinet, not capacities, and our hardware engineering guide explains the distinction between a test load and a manufacturer’s rating.

What every one of those tests has in common is the direction of the load. A drawer fails by having its front pulled off, its bottom pushed out, or its sides racked out of square, and the first of those is by far the most frequent, because it happens a little every time the drawer is opened. The joint between the side and the front is therefore the drawer box in miniature: whatever it does well, the drawer does well.

ANSI/AWI 0641-2019 leaves drawer box materials to the manufacturer’s option provided the assembled drawer meets the specified duty level, and then sets conditions by material: solid wood drawer boxes must comply with Custom Grade requirements under the AWI 300 materials standard, veneer drawer boxes must be at least ANSI/HPVA HP-1 Grade C, and decorative laminate drawer boxes must be HPDL or TFL with visible core not permitted at Premium grade. At Premium grade the edges of solid-stock drawer boxes must be stop-shaped or eased — profiled so that one profiled component does not butt against another — and the standard sets a maximum drawer box length of 558.8 millimetres, 22 inches, unless otherwise specified, with no more than 50.8 millimetres of clearance at the rear and 38.1 at the top.

A solid drawer side is a board, and a board moves. Our wood movement guide gives the arithmetic: wood changes dimension across the grain by roughly ten to a hundred times what it does along it, and a drawer side has its height across the grain. A tall solid side in a humid winter is taller than it was in August, which is why a solid drawer bottom floats in a groove and why the side is cut from a stable species — hard maple is the trade’s default, and the species guides explain why. Under a transparent finish a solid dovetailed drawer reads as furniture, and in a kitchen whose doors are inset and beaded it is the drawer the house expects.

A plywood side does not change height, and the Wood Handbook adds the property that matters for hardware: the alternating grain direction of its layers makes plywood resistant to splitting, allowing fasteners to be placed very near the edges of a panel. An undermount runner hooks the back of the drawer and locks the front with a clip screwed into the side near the bottom edge — Salice recommends pre-drilling at 2.5 millimetres for its clips to reduce the possibility of splitting the wood — and a veneer-core plywood side takes that screw without the risk a solid side carries. A dovetail cut across plywood holds well because the joint crosses alternating grain, and our plywood versus MDF guide explains why the same panel is the right one for the box the drawer slides into.

Look at the corner first. A dovetail shows its pins and tails on the side; a dowel joint shows nothing, or the ends of dowels if they are driven through; a lock joint shows a stepped line; a stapled butt joint shows staples. Then look at the bottom: a bottom captured in a groove on all four sides is a structural diaphragm that keeps the box square, as our cabinet box construction guide argues for the cabinet back, while a bottom stapled to the underside is a dust cover and a 250-pound compression test waiting to happen.

Look at the side material on its top edge. Solid wood shows grain through its thickness; plywood shows its plies; a particle or fibre panel shows neither, and under a drawer that will be thrown shut twenty thousand times it is the wrong material by the Wood Handbook’s own account of its edge strength. Then look under the drawer at the runner and the clip: the manufacturer’s name should be legible, the clip should be screwed into solid or plywood side near the bottom edge with no split, and the drawer should sit level and close with the damper engaging in the last inch or so.

The last thing to look at is the drawer front and how it is attached to the box. On a five-piece drawer with an applied front, the front is screwed through the sub-front from inside the box; on an inset drawer it is the box front itself, dovetailed to the sides. Either is correct. What is not correct is a front held on by the runner’s locking device alone, or a joint that flexes when the front is pulled sideways. The standards’ drawer tests are pull, push and rack, and a hand can apply all three in a showroom in less time than it takes to read a brochure.