Blum Undermount Drawer Slides

Blum Undermount Drawer Slides at a Glance

Blum Tandem Plus BLUMOTION slides mount beneath the drawer box, keep all hardware hidden, extend fully, and close softly without a slam. This is why production cabinetmakers switched from side-mounts, and why the same hardware shows up in high-end kitchens everywhere. Getting the install right comes down to two things: picking the H or F suffix based on your drawer side thickness, and cutting the drawer box width to exactly the right measurement.

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In this guide:

• Which model to buy — H vs. F, 563 vs. 569
• Sizing the drawer box before you cut
• Installation sequence, step by step
• Troubleshooting binding, tilt, and soft-close failures

Why Cabinet Makers Switched to Undermount

A side-mount slide has two telescoping rails: one screws to the cabinet side wall, the other to the drawer side. Ball bearings let them slide past each other. When the drawer is open, you see two chrome rails running the full depth of the cabinet. Each rail body is about 1/2" thick, so a pair eats roughly 1" of drawer width. Most side-mounts stop at 75% extension unless you specifically buy full-extension models.

An undermount slide mounts beneath the drawer box, not alongside it. The runner sits near the cabinet floor. The drawer box rests on top and clips onto the runner via a locking device (a spring-loaded clip at the front underside of the drawer box) that releases when you press its orange tabs. When the drawer is open, there's nothing visible on the sides. The drawer appears to float.

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Five things change when you switch:

All hardware disappears. No chrome rails visible when a drawer is open. The whole feel of a kitchen changes when you pull out a drawer and see nothing but wood.

Full extension is standard. You see the entire depth of every drawer.

Soft-close is built in. All current Blum Tandem Plus BLUMOTION models include the damping mechanism in the runner body. No separate purchase, no add-on kit.

You can adjust after installation. Four-way adjustment lets you dial in the drawer front gap after the cabinet is assembled. With side-mounts, if the gaps are wrong, you're re-drilling.

Quieter. Nylon rollers, no metal-on-metal contact.

The trade-offs are real. Undermount slides carry less load than heavy-duty side-mounts — the 563 series tops out at 100 lbs, vs. 500+ lbs for heavy-duty side-mounts used in file cabinets and tool storage. They cost more: $18–25 per pair vs. $8–12 for decent side-mounts. The drawer box width has to be cut to an exact measurement. Get it wrong by 2mm and you have a binding problem.

If you're building kitchen drawers, bathroom vanity drawers, or furniture with small to medium storage, undermount is the right call. If you're building a tool chest or heavy shop storage, heavy-duty side-mounts will serve you better.

The Blum Product Line: Which Model to Buy

H or F — the first decision

This suffix tells you which drawer side thickness the slide fits. Get this wrong and the drawer either binds (box too wide) or wobbles (box too narrow).

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Using 1/2" Baltic birch drawer sides? 563H. Using 3/4" plywood? 563F. Measure your actual sheet goods — plywood sold as "3/4" often measures 23/32" (18mm), which is within the 563F range.

Per Woodworker Express's 563H vs. 563F guide, the H and F models are otherwise identical: same mechanism, same soft-close, same load capacity.

563 vs. 569 — load capacity

563 series handles 100 lbs static load, comes in 9" through 21" lengths. This covers nearly every kitchen, bathroom, and furniture drawer.

569 series handles 150 lbs, comes in 18" through 33" lengths. Use it for pantry pull-outs, pot and pan drawers, and anything that regularly carries substantial weight. Woodworker Express confirms 150 lbs capacity for the 569H.

For most builders: 563H for standard drawers, 569H when the drawer will carry heavy loads.

Is BLUMOTION built in, or do you buy it separately?

Built in. All current Tandem Plus models (563H, 563F, 569H, 569F) have the BLUMOTION soft-close mechanism integrated into the runner body. As the drawer approaches closed, it decelerates and pulls in quietly regardless of how hard you push. No extra parts to install.

When to skip Tandem and look elsewhere

Blum Movento (763 series): Not an upgrade. A different system for push-to-open (TIP-ON) applications and very wide or heavy pantry pull-outs that need synchronized dual-rail stability. Starts at ~$31 per pair. For standard kitchen and furniture drawers, Tandem Plus BLUMOTION is the right tool.

LEGRABOX: A proprietary metal drawer box system. If you're building wood drawer boxes, skip it. It's not a slide for wood.

Tandem Edge BLUMOTION: The budget line. Same soft-close but fewer adjustability options and a 4mm setback instead of 3mm. Fine for budget projects.

For a standard cabinet with 1/2"–5/8" plywood drawer boxes, the answer is Blum 563H in the length matching your drawer depth.

Size Your Drawer Box Before You Cut

Sizing errors cause the most first-install failures. Getting these four measurements right before you cut anything prevents nearly all of them.

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Slide length = drawer depth

A 21" runner requires a 21" deep drawer box. They match exactly.

Inside drawer width formula

This is the dimension from one inside face to the other. Not the outside width of the drawer box.

For 563H (1/2"–5/8" sides): Inside width = Opening width − 42mm

For 563F (3/4" sides): Inside width = Opening width − 49mm

Tolerance: The finished inside width can be up to 1.5mm narrower than your target, but not wider. Wider causes binding. Narrower just adds a little side play.

Work in millimeters. Blum's specs are all in mm, and you'll be more accurate. Rounding fractions introduces errors that millimeters don't.

Example: Opening width 600mm, using 563H: 600 − 42 = 558mm inside drawer width. Cut sides so the inside dimension is 558mm (+0 / −1.5mm).

Hingmy's Blum drawer calculator generates a complete cut list from your opening dimensions if you want to double-check your math.

Per Sawdust Girl's Blum installation guide, getting this formula right is the single biggest factor in a first-install success.

Maximum drawer box height

Maximum drawer height = Opening height − 7/8" (approximately 22mm total)

The system needs:

• At least 7mm (9/32") clearance above the drawer box
• At least 14mm (9/16") below for the runner

Shorter than maximum is fine. Don't exceed maximum height.

The rear notch and hook hole

At the back of the drawer box, the runner passes underneath. Cut a notch in the bottom edge of the rear panel:

• Approximately 1/2" tall × 1-3/8" wide minimum

Above that notch, bore the hook hole:

• 6mm (1/4") diameter × 10mm (13/32") deep
• Use the Blum T65.1600 drilling template (~$15) for this hole and for the front locking device positions

The T65.1600 jig is worth buying. Per discussions on Woodtalk Online, hand-measuring the hook hole position is the most common source of installation failures on first-time installs. The jig positions both the rear hook hole and the front locking devices simultaneously.

Installing Blum Tandem Slides: Step by Step

Tools you need

• Drill
• 6mm bit (rear hook hole)
• 2.5mm bit (pilot holes for runner screws)
• Self-centering bit for locking device screws (prevents splitting)
• Phillips driver
• Tape measure and pencil
• Level or straightedge
• Blum T65.1600 drilling template (strongly recommended)

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Step 1: Prepare the drawer box

Before you touch the cabinet:

a. Cut the rear notch in the bottom edge of the drawer back panel.

b. Use the T65.1600 jig to bore the 6mm hook hole in the rear panel. The hook is what keeps the back of the drawer from shifting side-to-side and from lifting off the runner.

c. Position the front locking devices on the drawer box sub-front (the structural inner front panel, behind the decorative drawer face) using the same jig. Predrill with a self-centering bit. Use the screws Blum provides. A too-large flathead screw won't countersink flush and will bind against the runner as the drawer closes.

Locking device selection: For most standard kitchen and cabinet drawers wider than 170mm (6-11/16"), use the BT51.1901. This is the standard locking device with front side-to-side adjustment. Woodworker's Hardware's locking device guide walks through all five variants if your drawer is narrow or uses an inset face.

Step 2: Mount the runners in the cabinet

a. Determine runner height. For frameless (European-style) cabinets: center the runner 37mm (1-15/32") up from the cabinet floor. For face-frame cabinets: 10mm (13/32") up from the bottom of the face-frame opening, not the cabinet floor. These are different measurements and using the wrong one is a common error.

b. Set runner setback from front. For standard overlay: 3mm (1/8") from the front edge of the side panel or face frame. Mark this position on the cabinet side panel at two points. Per Woodworker's Hardware's setback reference, the 3mm setback applies to overlay doors; inset and other overlay types require different setbacks.

c. Position the runner using its elongated mounting holes. Don't tighten yet.

d. Check both runners are at exactly the same height. Use a level or measure from the cabinet floor. A 1mm difference creates side-to-side tilt on the drawer.

e. Drill 2.5mm pilot holes and drive screws, but leave them slightly loose until you confirm alignment with the drawer installed.

Step 3: Insert and test the drawer

a. Extend both runners fully toward the front of the cabinet.

b. Position the drawer box so the rear hook aligns over the hook hole, and the front locking devices align with the front of the runners.

c. Lower the rear of the drawer onto the runners first, then lower the front.

d. Push the drawer closed. You'll feel and hear a click as the locking devices engage. No click means the locking devices haven't seated. Stop and find out why before proceeding.

e. Open and close the drawer 2–3 times. It glides smoothly, closes fully, and the BLUMOTION engages in the last 2–3 inches. If any of those aren't happening, check the hook hole depth and locking device position before continuing.

To remove the drawer: Squeeze the orange release handles on both locking devices simultaneously while pulling the drawer out.

Step 4: Check and commit

With the drawer installed but runners still loose:

• Check the gap between drawer front and cabinet face. Is it even top-to-bottom? Left-to-right?
• Does the drawer front tilt forward (bottom gap wider than top)?
• Is the drawer centered in the opening?

Make preliminary adjustments now (see next section), then tighten the runner screws.

Per Woodworker Express's installation tutorial, load the drawer with its intended contents before making your final gap adjustments. Heavy loads shift the runner slightly, and gaps that look right empty will drift under load.

Four Adjustments That Dial In the Drawer Front

Blum gives you four ways to fine-tune the drawer front after installation. Each adjustment controls something specific. Spinning all four screws hoping something changes is the wrong approach.

Adjust in this order: tilt first, then height, then side-to-side. Tilt affects where the entire face sits relative to the cabinet opening. Get that right first.

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1. Tilt

Location: Gray lever at the rear of the runner, inside the cabinet. Direction: Twist lever upward (raise back of runner) to bring the drawer front closer to vertical. Range: Approximately 5mm (3/16") of rise. Use when: The drawer front tips forward — the bottom gap is wider than the top.

2. Height

Location: Small sliding tab on the bottom edge of the locking device. Direction: Slide toward the front to lower the drawer front; slide toward the back to raise it. Range: ±3mm (1/8"). Use when: Top and bottom gaps are uneven — the drawer front sits too high or too low overall.

3. Front side-to-side

Available on: BT51.1901 locking device only (not the basic BT51.1801). Location: Small cam screw on the locking device body. Direction: Clockwise moves the drawer front right; counterclockwise moves it left. Range: ±1.5mm (1/16") per side. Use when: The drawer front is off-center left-to-right. Critical: Adjust both sides equally. Adjusting only one side causes binding.

4. Rear side-to-side

Location: White plastic wheel at the rear of the runner, inside the cabinet. Use when: The drawer front looks parallel but the drawer runs crooked. It snags near the back on one side, or only squares up when you push from one corner.

This wheel moves the back of the drawer only. To shift the entire drawer front left or right, use both the front side-to-side (locking device screw) and the rear wheel together.

Troubleshooting: Five Common Problems

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Drawer won't click into place

Most likely cause: The rear hook hole position is off. The runner hook hits the face of the drawer back instead of dropping into the hole.

Fix: Remove the drawer. Confirm the hook hole is 6mm diameter and 10mm deep, positioned correctly per the T65.1600 jig. If drilled by hand measurement, re-bore using the jig.

Second cause: Locking devices are positioned too far forward or back on the drawer box sub-front. Confirm their position with the Blum jig.

Soft-close doesn't engage

Cause 1: The rear hook isn't fully seated. If the hook skims rather than drops into the 6mm hole, the locking device at the front doesn't fully engage, and BLUMOTION can't trigger. Check hook hole depth. It must be 10mm minimum.

Cause 2: Very light empty drawer. The damper needs some inertia to engage. Per LumberJocks forum discussion on Blum soft-close failures, this is normal. Load the drawer with its intended contents and the mechanism engages reliably.

Cause 3: Sawdust contamination. Wipe the runner and locking device with a damp cloth. Let dry completely before testing.

Cause 4: Wrong screws in the locking device. If you used #8 flathead screws that aren't countersinking flush, they catch on the runner body as the drawer closes. Replace with Blum's supplied screws.

Drawer tilts forward

Cause: The runner is angled down at the front, or the tilt adjustment at the back is set too low.

Fix: Use the gray tilt lever at the rear of the runner. Twist upward to raise the back of the runner and bring the drawer front closer to vertical. Make small adjustments. This lever is sensitive.

Drawer binds on one side

Cause 1: Runners are at different heights. One runner is higher than the other, causing the drawer to rack.

Fix: Loosen both runners. Place a straightedge across the runners from side to side. Level them at the same height before retightening. In frameless cabinets, both runners should measure 37mm from the cabinet floor.

Cause 2: Drawer box is not square. Diagonal measurements differ.

Fix: This requires remaking the drawer box. Clamp diagonally while the glue is wet. Check with a large square or by measuring diagonals before final assembly.

Drawer front is off-center after adjusting

Cause: You're adjusting the front locking device screw, but the real problem is rear alignment.

Fix: Adjust the rear white wheel first to align the back of the drawer. Then use the front side-to-side screw to fine-tune the face. The front and rear adjustments work independently.

Where This Fits in Your Cabinet Build

Undermount slides are the last step in building a drawer, not the first. Before you install slides, you need a cabinet carcass that's square and a drawer box that's dimensioned correctly.

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Read these first if you haven't:

• How to Build a Cabinet — the box needs to be square and the side panels need to be plumb before slides will work correctly
• Sheet Goods for Cabinets — Baltic birch plywood for drawer boxes, minimum 1/2" sides for 563H
• Frameless Cabinet Construction — runner mounting differs (37mm from floor, screws directly to side panel)
• Face-Frame Cabinet Construction — runner mounting differs (10mm from face-frame bottom, rear bracket required)

After the slides are in:

• Attach the decorative drawer front to the drawer box sub-front with screws from inside the box
• Use pocket hole joinery for sub-front attachment if you need adjustability

A correctly installed Blum Tandem Plus BLUMOTION drawer opens with light finger pressure from any point on the front, extends fully, and closes to a soft, even click regardless of how hard you push. When all four gaps are even and the BLUMOTION engages consistently, the slide installation is done.

Sources

These guides and resources informed this article.

• Woodworker's Hardware Tandem Guide — locking device selection, measurements, and adjustments
• Woodworker Express: How to Install Blum Tandem Slides — step-by-step installation tutorial
• Woodworker Express: 563H vs. 563F — H/F suffix confirmed
• Woodworker Express: Tandem load capacity — 563 and 569 load ratings
• Woodworker Express: Tandem vs. Movento — when to use Movento
• Blum Official: Tandem product overview — current product lineup
• Blum Official: Tandem assembly and videos — installation docs and 8-part video series
• Blum Official: BLUMOTION overview — damping mechanism details
• Woodworker's Hardware: Runner setbacks — setback measurements by overlay type
• Sawdust Girl: Tandem installation guide — locking device choices and drawer sizing
• Hingmy Blum drawer calculator — drawer box cut list calculator
• Hardware Hut: T65.1600 drilling template — jig specs
• LumberJocks: Soft-close failure root causes — light drawer diagnosis
• Woodtalk Online: Drawer dimensions forum — practical width formula discussion
• Woodweb Cabinetmaking Forum: Blum vs. Grass comparison — professional cabinetmaker perspectives