Drawer slides differ by manufacturer. The majority of them install similarly, and two common types exist: under-mount and side-mount. Under-mount, or bottom-mount, slides are concealed when the drawer extends, while side-mounted slides tend to support more weight. Another type, with a single center mount, typically appears on cheap cabinets and provides less stability. Full-extension versions of bottom- and side-mount slides allow the drawer to pull completely out of the cabinet. These install similarly to standard slides.

Notebook and pencils in open desk drawer top view
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How to Install Drawer Slides

Tolerance Differences in Bottom-Mount and Side-Mount Slides

Cabinets with face frames use bottom-mount slides. Bottom-mount slides adapt to a wide variety of styles and measurements. With allowable tolerances of 1/2 inch between the drawer and face-frame, bottom-mount slides are ideal for replacing older wooden slides, as new additions to older cabinets without existing slides or as a component in new cabinets.

Side-mount slides typically pair with frameless (otherwise known as European-style) cabinets. Side-mounted slides are close-tolerance, meaning that there can be little variation in the cabinet, with no more than a 1/8-inch gap between the top of the drawer and the top of the cabinet opening.

Understanding the Markings: Left and Right Designations

The instructions for installing slides are basically the same for bottom-mount and side-mount, simply with a different location of the slides. First, identify the parts. Open the package and separate the slides into four pieces. One end of each slide should be marked or stamped with the letters DR, DL, CR or CL. The slide stamped DR represents the right side of the drawer; DL marks the left side of the drawer; CR means the right side of the cabinet; and CL means the left side of the cabinet. The stamped letters typically appear on the front of the slide — that is, the end facing the front of the drawer.

Installing a Bottom-Mount Slide

Using a drill or screwdriver and the screws provided with the kit, screw the slide marked DR to the bottom right of the drawer. The slide should fit flush and behind the drawer front. Use the oval-shaped screw holes (one in front and one in back). Center the screw in the oval-shaped hole.

Screw the slide marked DL to the bottom left of the drawer in the same way. Screw the slide marked CR to the horizontal rail on the right side of the cabinet drawer opening using two screws, centered in the oval-shaped screw holes in front and back.

If you can see a horizontal rail in the back, the slide attaches to it. If no rail exists in the back, the slide utilizes a boot that attaches to the back of the cabinet. Repeat by screwing the CL slide to the left side. Fit the drawer's slides into the cabinet's slides, and push the drawer into the cabinet.

Installing a Side-Mount Slide

Side-mount slides screw centered to the side of the drawer. Using the designated marks — DR, DL, CR and CL — screw the slides to their respective locations on the sides of the drawer and on the sides of the cabinet. Depending on manufacturer, the use of a square may be necessary to level the cabinet slide horizontally before screwing it to the side of the cabinet. Some varieties of side-mount slides screw to the side of the drawer flush along the bottom instead of centered.

Installing Center-Mount Slides

Center-mount slides contain only two slides: one for the drawer and one for the cabinet. These slides typically contain only a "C" mark for cabinet and "D" mark for drawer. Some versions, depending on how the drawer is built, call for a wooden support to be installed for the cabinet guide, or for the drawer to be modified by cutting a notch on the bottom for the slide.

Center-mount slides screw to the drawer and cabinet centered in the opening. Oval-shaped screw holes may or may not exist for adjustment. Center-mount slides are very forgiving, so expect some sideways movement.

Final Step: Adjust for Smooth Action

The key to smoothly operating drawers is in the adjustment. The oval-shaped holes provide the adjustment. If drawers are sticky, rub, grind or seem loose, loosen the screws and tap the slides in the direction needed so that the drawer moves in and out smoothly. Models of side-mount slides may have cam-operated levers that are operated with a screwdriver to lift or lower the slides. When the drawers operate smoothly, add the remaining screws to all the screw holes in the slides.