Guides
How to install drawer slides
Every drawer slide screws, clips or hooks onto two surfaces, the cabinet and the box, and most installs go wrong for one reason: the box was the wrong width for the slide. Get that right and the install itself is a few turns of a screwdriver. This guide walks the side mount ball bearing install in full, since it is the slide in most kitchens, dressers and shops, then points you to the right page for soft close, bottom mount, center mount, undermount and a straight slide swap.
Quick answer. The box is the cabinet opening minus 1 in for side mount ball bearing slides, 1/2 in of clearance on each side, and the box depth matches the slide length. Screw the cabinet members in level and parallel, the drawer members onto the box sides, then join the two. Undermount runners need a box notched and drilled at the back instead; see our undermount install guide for that version. Gritly builds the box to the right width for your slide and stocks Würth side mount slides.
Before you start: measure and match
Two numbers decide the box before you pick up a screwdriver. Width is the cabinet opening minus 1 in, 1/2 in of clearance on each side, for side mount ball bearing slides. Depth matches the slide length, not the cabinet depth.
- Width. Opening minus 1 in, 1/2 in of clearance per side. A 24 in opening takes a 23 in box.
- Depth. Matches the slide length. Gritly’s Würth PRO 3.0 and PRO100 side mount slides come in 10 to 28 in, even lengths, both rated 100 lb per pair.
Measure the opening and the old slide, not the drawer front, before you order either one. Our how to measure drawer slides guide covers both cases, an old box in hand or an opening with nothing in it.
How to install side mount drawer slides
You need a tape measure, a square, a pencil, and a screwdriver or a drill with a driver bit, plus the new slides and a box built to the width above. Work one side at a time so the two slides stay matched.
Separate the members
Most side mount slides come apart on the bench: extend each slide fully and press its release lever or tab to pull the inner member free, so you have two cabinet members and two drawer members.
Mark a level line in the cabinet
Measure up from the cabinet floor, or down from the underside of the opening, and mark the same height on both sides, square to the front, so the slide runs level and parallel front to back.
Screw the cabinet members to the line
One member per side, along the line you marked, with the screw size the slide maker calls for.
Screw the drawer members to the box sides
One member on each side of the box, flush with the front edge, at the same height as the cabinet members.
Insert the box
Pull the cabinet half of each slide all the way out, line the drawer members up with it and push the box in until it seats; expect a little resistance the first time.
Test and adjust
Open and close it a few times. If it binds or sits crooked, most side mount slides have slotted mounting holes; loosen the screws, shift the member slightly, and retighten.
Face frame cabinets
A frameless cabinet gives the slide a flat cabinet side to screw straight into. A face frame cabinet usually sits the frame stile proud of the cabinet side, so the slide needs help reaching it: spacers block the cabinet side out flush with the frame, or a rear mounting bracket hangs the back of the slide from the cabinet back while the front screws to the frame. Either fix uses the same opening minus 1 in box; our drawer slide spacer guide covers measuring the offset and picking a thickness.
Soft close side mount slides
Soft close uses the identical box as plain side mount: same width, same depth, same plain sides. The damper lives inside the slide, not the box, so the install does not change; screw the cabinet and drawer members on the same way and insert the box. Buy the soft close pair in the same length as your old slides. Our soft close side mount slides guide covers what changes and what it costs to upgrade.
Bottom mount and center mount slides
Bottom mount epoxy roller slides screw along the bottom edge of the box on one rail and to the cabinet side on the matching rail, with a nylon wheel riding in each; pull the drawer to the stop and lift the front up and over to free it. Center mount is a single rail that runs under the middle of the drawer, front to back, with the drawer riding on the rail instead of hardware on the sides. Our bottom mount and center mount guides cover sizing the box for each.
Undermount slides
Undermount runners hide completely under the box, so the box needs a notch and a hook hole at the back and locking clips at the front, instead of the plain sides that side mount and bottom mount use. Our undermount install guide walks mounting the runners and hanging the box step by step, and if you are moving an existing side mount drawer over, converting to undermount covers the box change. Once the box is hung, Blum’s T51.1901 locking devices for TANDEM adjust it up to 1/8 in in height and 1/16 in side to side without tools, so a box that sits a little off still centers in the opening; our how to adjust undermount drawer slides guide walks each adjustment.
Drawer slide types at a glance
Every type uses a different box and mounts a different way. Gritly builds the box to match whichever one you pick.
| Spec | Side mount | Bottom mount | Undermount |
|---|---|---|---|
| BOX SIDES | Plain; the slide screws to the flat side | Plain; the rail screws to the bottom edge | Notched and drilled at the back, locking clips at the front |
| BOX WIDTH | Opening minus 1 in | Opening minus 1 in, same as side mount | Set by the runner, not one deduction; see our undermount slide guide |
| CLEARANCE PER SIDE | 1/2 in | 1/2 in | Set by the runner |
| SOFT CLOSE | An option on the slide, same box either way | Rare; most are self close, not damped | Built into the Blum and Würth runners Gritly stocks |
| GRITLY SELLS | Würth PRO 3.0, PRO100, PRO100SC | Standard size boxes with bottom mount slides on | Blum TANDEM, MOVENTO and Würth PRO600 |
How to replace drawer slides
Take the old pair off the box and the cabinet the same way you would remove any drawer: release the members and unscrew both halves. Buy a new pair that matches the old one in length and type, side mount for side mount, undermount for undermount, since mixing types means a new box, not just new hardware.
- Take the old pair off. Release the members and unscrew both halves from the box and the cabinet.
- Match the replacement. Same length, same type as the old slide; a different type needs a different box.
- Reuse the holes only if they line up with the new member. Otherwise drill new ones and fill the old holes.
The side mount width rule
Every side mount ball bearing box follows the same rule, whatever the opening measures.
Drawer slide installation questions
How do I install side mount drawer slides?
Build or order the box the cabinet opening minus 1 in, then separate the slide members and screw one cabinet member to each side on a level, parallel line. Screw the drawer members to the box sides, flush with the front, at the same height, then slide the box in until it seats. Test the glide and adjust with the slotted mounting holes if it binds or sits crooked.
How do I install drawer slides in a face frame cabinet?
The same box and the same side mount slide, with one extra step: block the cabinet side out flush with the face frame first. Use drawer slide spacers in 1/2 to 1 1/2 in thicknesses, or a rear mounting bracket that hangs the back of the slide from the cabinet back. Either fix keeps the box at the opening minus 1 in width.
How do I install soft close drawer slides?
The same way as plain side mount, since the box and the steps do not change. Screw the cabinet members in level and parallel, the drawer members to the box sides, then insert the box; the damper lives inside the slide and catches the drawer in the last couple of inches. Buy the soft close pair at the same length as your old slides.
How do I install roller drawer slides?
Line the rails up level, screw them on with the screw size the slide maker calls for, then set the box on the cabinet rail and push it in. Roller drawer slides, also called bottom mount epoxy slides, screw along the bottom edge of the box on one rail and to the cabinet side on the matching rail, with a nylon wheel riding in each. They take the same opening minus 1 in box as side mount.
What size undermount drawer slides do I need?
Match the runner length to the box depth, and check the cabinet’s inside depth, since each runner needs a minimum depth to fit. The box width then follows that runner’s own rule, not one fixed deduction. Our undermount slide guide covers sizing by runner, including Blum TANDEM and MOVENTO, and the undermount install guide walks the mounting steps once the box is in hand.
How do I replace drawer slides?
Take the old pair off the box and the cabinet, the same release you would use to remove the drawer, then unscrew both halves. Buy a matching pair, same length and the same type as the old one, since a different type needs a different box. Reuse the old screw holes only when they line up with the new member. Our replacement box install guide covers moving the front over too.
Do full extension and 3/4 extension slides install the same way?
Yes. Both mount to the identical plain sided box, at the same opening minus 1 in width, so the choice between them changes nothing about the install. Full extension brings the drawer out to the face of the cabinet; 3/4 extension stops with part of the drawer still inside. The box does not change either way.
Where can I buy Blum undermount drawer slides?
Gritly stocks Blum TANDEM and MOVENTO undermount runners, along with Würth PRO600, and notches and drills the box to match at no charge. Buying the box and the runner together means the fit is already accounted for before either one ships.
What tools do I need to install drawer slides?
A screwdriver or a drill with a driver bit, a tape measure, a square or a level, and a pencil to mark the line cover every slide type on this page. A slide mounting jig is a helpful extra that holds the member square while you drive the screws, but none of the steps need it.
Build the box, then install your slides
Measure the opening, pick your slide, and order a box built to that width, cut to the 1/32 in. Dovetailed and built in our Las Vegas shop, ready for the steps on this page the day it arrives.