How to Install Undermount Metal Box Drawers? Can Existing Drawers Be Converted to Metal Box Slides?

As modern furniture trends move toward sleek minimalism and superior functionality, undermount metal box drawers have become increasingly popular in kitchens, wardrobes, and office systems. But how do you install them? And is it possible to upgrade your existing drawers to this premium system?

In this article, we’ll walk you through the basics of installation and explore whether retrofitting existing cabinetry is feasible.

How to Install Undermount Metal Box Drawers

Installing undermount metal box drawers is a relatively straightforward process—especially if you’re using a pre-assembled system. Here's a general step-by-step guide:

1. Prepare the Cabinet

Ensure that the cabinet is square and the inner sides are smooth and even.

Check the cabinet depth to match the slide length (typically 270mm to 550mm).

Install the rear brackets (if applicable) or attach the slides directly to the cabinet side panels or rear wall.

2. Mount the Undermount Slides

Fix the undermount slides onto the bottom of the cabinet using the designated screw holes.

Ensure both slides are level and aligned with each other front to back.

Use a spirit level for accuracy to avoid future drawer misalignment.

3. Assemble the Drawer

Most metal box drawers come with:

Two metal sides

A back panel (wood or metal)

A wooden base panel (usually 16mm thick)

Locking devices for connection with the undermount slides

Slide the panels together according to the manufacturer’s guide and secure them with screws or clips.

4. Attach Locking Devices

Install the front locking devices under the drawer box.

These help secure the drawer to the slides and allow for easy removal when needed.

5. Insert and Adjust

Align the drawer box above the slides and push it in gently until you hear a “click”—this means the drawer is locked into place.

Use the integrated front adjusters to fine-tune vertical and lateral alignment so the drawer face sits flush and even.

Pro Tip:

Some systems offer tool-free installation and 3D adjustment features, allowing height, depth, and tilt corrections without removing the drawer.

Can Existing Drawers Be Converted to Metal Box Slides?

This is one of the most frequently asked questions by furniture makers and renovators—and the answer is: it depends.

Feasible When:

The existing cabinet has enough internal space and the correct depth.

You're willing to replace the entire drawer box, not just the slides.

Metal box drawer systems are not retrofit-compatible with typical wooden drawers used in side-mount or bottom-mount setups. This is because:

Undermount slides require a special groove on the drawer bottom.

The drawer sides must match the metal box system's height and structure.

Most undermount systems rely on locking devices and pre-drilled metal panels.

Conversion Process (if upgrading):

Remove the old drawer and slides.

Measure cabinet dimensions carefully.

Order new metal box drawer kits (including drawer sides, back panel, base panel, and undermount slides).

Follow the standard installation steps to mount the slides and assemble the new drawer.

In short: a full drawer replacement is necessary to use undermount metal box systems.

Final Thoughts

Installing undermount metal box drawers is a smart upgrade for achieving modern design, smooth motion, and hidden hardware. While installation is relatively simple with the right tools and instructions, retrofitting old drawers is usually not practical without replacing the entire drawer box.

For new builds, these systems are ideal. For renovations, it’s a great opportunity to refresh both the appearance and function of your furniture.