Undermount soft-close slide

Overview

An undermount slide sits under the drawer box rather than at its sides. A cabinet rail is screwed to the carcass side, and the drawer clips onto the slide with locking devices screwed into the drawer's underside. The result is a drawer whose sides are clear of hardware, so it shows only wood, and a soft-close damper that stops it slamming. Wikipedia's drawer entry describes soft-close mechanisms and full-extension telescoping slides, both of which this type offers.

Types and sizes

• Length from 250 to 550 mm (10 to 22 in), chosen to match the drawer depth.
• Locking devices (brackets) fix to the drawer bottom and hook onto the slide; they adjust for height and tilt.
• Side thickness: 12 to 16 mm (1/2 to 5/8 in) solid sides are typical; the drawer bottom is in a groove, and the back is notched to clear the rear hook.
• Soft-close is almost always built in, with a push-to-open version.
• Capacity is the maker's rating, usually 30 to 45 kg (65 to 100 lb).

Where it is used

Modern kitchens, bathroom vanities and high-end casework, where the dovetailed or box-joint drawer sides are meant to be seen. It is not a period detail.

Choosing and sizing

Use the maker's drawer-size sheet: drawer length, width, bottom position and back notch are all specified. Drawer sides under 12 mm (1/2 in) cannot hold the brackets. Choose the slide length to leave a few millimetres at the back. The width allowance is normally the opening minus a fixed amount, so build the box to that figure, not to the opening.

Installation

1. Build the drawer box to the maker's template: side height, groove height from the bottom edge, notch at the back.
2. Fix the cabinet slides level, in a line with each other, set back from the front by the maker's figure (often 3 to 5 mm, about 1/8 to 3/16 in).
3. Screw the locking devices to the drawer bottom on the lines the sheet gives.
4. Hook the drawer on; adjust the height and tilt with the adjusters.
5. Test the soft-close: it needs the drawer to be square and not rubbing.

Wood movement and species

The drawer box, being narrower than the opening by a fixed figure, has no allowance for seasonal change in wide solid sides, so use quartersawn or plywood sides (Hard maple or Baltic birch plywood) and keep the drawer box width to the maker's tolerance. A solid-wood bottom set into a groove should be free to move; a glued-in bottom will crack against the brackets.

Common mistakes

• Drawer bottom too thick for the groove: it will not seat.
• Notch cut too short at the back: the drawer will not hook on.
• Cabinet rails not parallel: the drawer binds.
• Using solid sides under 12 mm (1/2 in) thick: the brackets split the wood.

Related

• Side-mount ball-bearing slide: visible but simpler and cheaper.
• Wooden drawer runner: traditional runners, no metal.
• Wood screw: pilot holes for the brackets.