Guides

Notched drawer boxes: the rear notch and hook holes, by slide model

By Dale McCoy, head of production · Technically reviewed by Tory O’Neal · Updated October 2026

An undermount drawer slide does not screw to the side of the box the way a side mount slide does. It carries the box from underneath and hooks into the back of it, so the box needs a notch cut into each bottom back corner and a hole drilled for the hook. Every slide maker publishes its own notch size, hook position and width rule, and this page is the index: what the notch and hook hole actually do, why we cut them, and a full table of every model we notch for, with a dedicated page for each one.

Ready to build it? The configurator cuts the notch and drilling free once you pick your slide.

Why we notch instead of just shortening the back

An undermount runner needs two things from the box: the bottom captured at the right height so the runner can carry it, and a place at the back for the rear hook to seat, which is what keeps the drawer from pulling all the way out when you yank it. A notch cut into each bottom corner does both without giving anything up: the bottom still runs in a groove on all four sides, same as a plain dovetail box, and the back panel still closes off the back of the drawer above the notch. Blum’s own documents note a shortened back panel with the bottom run out to the back as an alternative, but we notch, because a full height back with a notch keeps the bottom captured and gives a cleaner result on a dovetailed box.

The hook hole is separate from the notch and easy to miss on a drawing: it sits above the notch, drilled into the back face of the back panel, not into the notch itself. Get the hole position wrong by even 1/8 in and the hook will not seat fully, which usually shows up as a drawer that will not pull home or that rattles at the back.

Finding your slide model

Pull the drawer and look at the metal runner screwed to the cabinet, or the box you are replacing. Most makers stamp or print the model number on the side of the runner near the back: Blum prints “563” or “763” plus a length code, Grass prints “Dynapro,” Salice prints “A7555,” “A7955” or a “G5U” or “G7U” part number, and Würth’s PRO series prints “PRO” plus three digits. Match what you read to the table above and open that model’s page for the exact notch, hook hole and width rule, so you order a Blum ready drawer box on the first try. If nothing matches, choose Other or unlisted slide model in the configurator, or read our other undermount slides page.

Every model page follows the same shape: the drawer box dimension by dimension, the rear notch and hook hole with a drawing, what the slide itself is rated for, the clip and whether we install or sell it, the depths we build, a worked example from an opening to a finished box size, and the mistakes we see most. Each links back here and across to the brand comparison guide, which groups the same runners by maker with the full manufacturer drawings.

Questions

What is a notched and drilled drawer box?

A dovetail drawer box with a rectangular notch cut into each bottom back corner and a hole drilled above it for the slide’s rear hook, sized to your exact undermount runner. The front gets pre drilled holes for the locking device too. We cut both free on any custom box with Notching set to “Notched & Drilled For Undermount Slides.”

Do I subtract anything from my opening width myself?

Yes. You work out the outside box width from your runner’s rule, usually the opening minus 10 mm (13/32 in) with 5/8 in sides, and enter that number. We cut exactly what you enter and make no deduction of our own on a notched box.

Is the notch the same size on every undermount slide?

No. Most runners clear a 35 mm notch, but Blum MOVENTO needs 50 mm (125 mm with TIP-ON), Salice Progressa needs 50 mm, and Salice Futura uses a 7 mm hook hole instead of 6 mm. Always use the notch and hole for your actual model, not a generic figure.

Can I order a notched box with a fractional depth?

No. Undermount runners come in whole inch lengths, so the box depth has to match exactly and the depth fraction stays at zero. Width and height still go to the 1/32 in on a notched box.

What if my slide is not in the configurator list?

Choose Other or unlisted slide model and type the brand and model printed on the runner. We match the notch, hook hole and width rule to that model’s published spec before cutting.

Do you install the front locking device for me?

Where we know the part number for your model, yes, for $5.99, pressed on before shipping. Where we do not stock the part, the holes are still drilled and you press your own clip on in seconds.