Undermount slides give you three adjustments so the drawer front can sit perfectly flush and even with everything around it. Once you know where the three adjusters are, squaring up a front takes about a minute per drawer. Here is each one on a Blum undermount set.
Quick answer. Undermount drawers adjust at the front locking clips under the box, not on the runner. Most clips set height and side to side, a basic clip like Blum’s T51.1801 sets height only, and depth comes from clips or add ons that offer it, such as the 298.7600 depth adjuster on MOVENTO. Pull the drawer out, adjust a little at a time, and check the gaps against the drawers around it. Gritly notches every custom box to the slide you choose, so the clips only fine tune a box that already fits.
The three adjustments
All three live at the front of the slide, on or beside the locking devices under the box. Pull the drawer fully out to reach them. The adjusters cover only a few millimeters each, so they fine tune a well fitted box. They cannot rescue a box built to the wrong size.
| ADJUSTMENT | FIXES | WHERE |
|---|---|---|
| Height, up and down | Front too low or too high | Wheel on each locking device |
| Side to side, tilt | Front cocked left or right | Lateral adjuster on the locking device |
| Depth, in and out | Front proud or sunk in the opening | Front lever or cam on the locking device |
Height: raise or lower the front
Each locking device has a small wheel or dial. Turn both the same amount to lift or drop the whole front. Turn one more than the other to level a front that leans. Do it in small steps and check the reveal against the drawer above and below.
Side to side: straighten a tilted front
If the front sits square to the box but leans in the opening, use the lateral adjuster on the locking device to shift the front left or right a couple of millimeters until the gaps on each side match.
Depth: set the front flush
The depth adjuster pulls the front in or pushes it out so it lands flush with the cabinet face and the neighboring fronts. On most Blum sets this is a small lever or cam you turn on each locking device. Adjust both sides evenly so the front stays square.
If adjustment runs out of room
The adjusters only cover a few millimeters. If a front is still off after you max one out, the runners were mounted at slightly different depths or heights; reset the runner on that side and start over. Runner placement is covered in how to install undermount slides. And if the drawer runs rough or the box wobbles no matter what you turn, the problem is the slide or the box, not the adjustment. See why won’t my drawer close to sort out which.
Building a new drawer for an undermount slide? Configure one to the 1/32 inch and pick your slide model on the custom box configurator. It arrives notched for the exact slide so the fit starts right.
Adjustment parts, from our shop
If a locking device is cracked or you want more adjustment range than the basic clips give, we stock the upgraded parts.
Undermount adjustment questions
Why does my undermount drawer front sit crooked?
Usually one locking device is set higher than the other, or the front was mounted before the box was squared on the runners. Level it with the height wheels first, then use the side to side adjuster to even the gaps.
How much can undermount slides adjust?
Only a few millimeters in each direction: height, side to side and depth. They fine tune a front; they cannot fix a box that is the wrong size for the runner.
What if an adjuster is maxed out and the front is still off?
The runners were mounted at different heights or depths. Reset the runner on the low or deep side so both match, return the adjusters to center, and dial the front in again.
How do you adjust Blum drawer slides?
Blum undermount drawers adjust at the front locking clips: the T51.1901 clip on TANDEM sets height and side to side, the basic T51.1801 sets height only, and MOVENTO takes the 298.7600 depth adjuster for front to back. Adjust a little at a time and check the gap against the drawers around it. Gritly notches every custom box to the Blum runner you pick, so the clips only fine tune the fit.
How do you adjust soft close drawers?
Soft close comes from a damper built into the slide, so if the drawer stops short, check for binding, debris or a box that hits the cabinet back before you touch the clips. The clips still square up the front if it sits crooked. If the soft close has stopped working entirely, see why won’t my drawer close for the common causes.
How do you adjust undermount slides?
At the front locking clips under the box: most set height and side to side, and some add a depth adjustment. Turn each adjuster a little at a time until the front sits even with its neighbors. Each one covers only a small range, enough to square up a box that already fits the runner, not to correct a box of the wrong size.