Kitchen Door Hinges and Drawer Runners: Blum vs Grass Hinge Adjustment, Soft-Close Mechanisms, Push-to-Open and Tandem Box Drawers

Summary

Kitchen door and drawer mechanics are what separate a kitchen that works from one that frustrates. Doors that are misaligned, stiff to open, or slam shut damage the client relationship — and the units. Understanding the adjustment system of the two dominant hinge brands (Blum and Grass) means that any cabinet that arrives correctly made and incorrectly hung can be adjusted on site in minutes.

The move toward handleless kitchens has driven significant product innovation. Push-to-open (Blum TIP-ON, Grass TIPMATIC) allows doors and drawers to open with a finger push, eliminating the need for handles entirely. This requires a different hinge specification — the damping and spring force must be calibrated to the door weight, and the door gap must be tight enough to operate the mechanism.

Soft-close is now effectively universal in new kitchen installations. It is achieved either through an integral damper in the hinge (Blum Clip Top Blumotion, Grass Nexis Soft-Close) or through a separate damper added to the mounting plate (Blum Blumotion add-on). Drawer soft-close is built into the runner mechanism in all current Blum and Grass tandem/legrabox systems.

Key Facts

• Hinge cup size: 35mm diameter is universal for concealed European hinges (Blum, Grass, Hettich, Hafele all use 35mm cup)
• Standard overlay: full overlay (door covers full face of cabinet side) = 18mm overlay; half overlay = 9mm; inset = 0mm
• Drilling position for full overlay: cup hole centre 22.5mm from door edge (for 18mm overlay doors — check manufacturer specification)
• Hinge mounting plate height: typically 37mm (standard) but check manufacturer — affects door height relative to cabinet
• 6-way adjustment: lateral (L/R), depth (F/B), vertical (U/D) — each ±2mm per axis
• Blum Clip Top Blumotion: soft-close integral in hinge body; 'Blumotion' suffix identifies soft-close version
• Grass Nexis soft-close: damper integrated into hinge arm; identified by 'S' suffix on part number
• Opening angle: standard 110°; wide-angle hinges available (155°) for tall larder doors and corner units
• TIP-ON force: adjustable; standard kitchen door 1,600–2,200g door weight = 'M' power
• Blum Tandem Plus: side-mount steel runner; max load 30kg; lengths 270–600mm
• Blum Legrabox: full side panel replacement system; load to 70kg; 116mm nominal height
• Grass Nova Pro Scala: alternative to Legrabox; 70kg load; full extension
• Drawer runners full extension: all current domestic ranges include full extension (drawer pulls out to full depth); push for 3/4 extension on budget ranges

Quick Reference Table

Detailed Guidance

Concealed Hinge Adjustment — Step by Step

All European concealed hinges (35mm cup) share the same three-axis adjustment principle, regardless of brand. The screws may be in different positions, but the function is identical.

Before adjusting — identify the problem:

• Door too far left/right relative to adjacent door → lateral adjustment
• Door sticking out or too far in relative to adjacent door → depth adjustment
• Door too high or low relative to adjacent door → vertical adjustment
• Door not closing flush at one corner → combination of lateral and depth

Lateral adjustment:

• Open the door fully
• The side adjustment screw is the long screw on the front face of the hinge arm (closest to the door edge)
• Turning clockwise moves the door toward the hinge side; anti-clockwise moves it away
• Adjust in small increments (quarter turns); close door to check after each adjustment
• Adjust all hinges on the door by the same amount to keep the door parallel

Depth adjustment:

• The depth screw is on the mounting plate (the part fixed to the cabinet), usually an eccentric cam
• On Blum: the cam screw rotates to move the hinge arm in or out
• On Grass: a front-face screw on the mounting plate
• Moves the door face in (recesses it) or out (brings it forward)
• Use this to align a door that is flush at top but proud at bottom (sign the door is twisted)

Vertical adjustment:

• The mounting plate usually has a vertical slot
• Loosen the fixing screw(s), slide the plate up or down, retighten
• Adjustment range is typically ±2mm per plate; for more, reposition the plate in a different hole

Hinge Selection by Application

Soft-Close Hinges

Blum Clip Top Blumotion: The soft-close mechanism is built into the hinge body. When the door is closed to within 15° of the closed position, the damper activates and controls the closing speed. The damping force is adjustable on some versions (screw on the hinge body) but most domestic versions are factory-set.

Important: Blum soft-close hinges will not work correctly on very light doors (under 400g) — the spring force is insufficient to pull the door closed against the damper resistance. Solution: increase the spring tension (a screw on some models) or use a lighter damping add-on.

Grass Nexis S (soft-close): Very similar functionality. Identified by 'S' at end of part number. Damping integrated into hinge arm.

TIP-ON (push-to-open): The TIP-ON mechanism is a separate latch fitted to the cabinet carcase (not to the hinge). When the door is closed, the latch catches it. Pushing the door activates the TIP-ON, which kicks the door open 20–30mm. Available for both doors (TIP-ON for hinges) and drawers (TIP-ON Blumotion for Tandem Plus).

For TIP-ON to work correctly:

• Door must be within 1mm of target gap (typically 1–2mm gap when closed)
• Door must be the correct weight class for the TIP-ON model selected (light, medium, heavy)
• The hinge itself does not need to be a TIP-ON version — the mechanism is in the cabinet-mounted latch

Drawer Runner Systems

Blum Tandem Plus (side-mount, steel):

• 12mm thick runner on each side of drawer
• Load rating: 30kg full extension
• Integrated Blumotion (soft-close) available as 'Tandem Plus Blumotion' version
• Available in 270, 300, 350, 400, 450, 500, 550, 600mm lengths
• Drawer height: side panel height varies; must match runner specification

Blum Legrabox (undermount, full side panel):

• Concealed runner — runner is hidden inside the drawer side
• Load rating: 40–70kg depending on version (F = 40kg, N = 70kg)
• Available in four side heights: 83mm (XS), 93mm (S), 116mm (M), 138mm (M with railing)
• Full extension with integrated Blumotion
• Legrabox sides replace the drawer sides — no separate wooden sides needed

Grass Nova Pro Scala (undermount):

• Direct competitor to Legrabox
• 70kg load; 115mm or 185mm side heights
• Integrated soft-close and TIP-ON

Adjusting drawer runners:

• Height adjustment: most modern undermount runners adjust ±2mm vertically via screw on the runner head
• Lateral adjustment: ±2mm side screw on the runner
• Front-to-back adjustment: loosen the runner's carcase fixing screws and slide

Frequently Asked Questions

A door keeps swinging open slightly after being pushed closed — what's wrong?

Either the soft-close hinge is not correctly activated (door gap too large — TIP-ON latch not engaging), the hinge spring force is insufficient for the door weight, or there's a magnet catch that has lost its strength. For soft-close hinges without TIP-ON, check that the door is actually reaching the closed position (measure the gap with a thin feeler gauge — should be 1–2mm). If the hinge spring is weak, replace the hinge — the spring is not serviceable on most domestic hinge types.

How do I know which Blum hinge part number I need to replace?

The part number is stamped on the hinge arm (look with a torch, usually on the underside or side of the arm). Blum part numbers follow the pattern: 71T3550 (Clip Top standard, 110°, full overlay) or 71B3550 (Clip Top Blumotion). The third and fourth characters indicate the opening angle and overlay. Alternatively, photograph the hinge and use Blum's online finder (blum.com) which can identify from photos.

A Tandem Plus drawer is stiff to close — it doesn't self-close smoothly. Why?

Check: (1) Is the runner the correct length for the cabinet depth? An undersize runner puts the drawer at the limit of its travel. (2) Is the drawer weight within the runner rating? Overloaded runners stiffen. (3) Is the Blumotion damper activated? Tandem Plus Blumotion has a switch on the runner that can be set to 'active' or 'inactive'. (4) Is the runner level side-to-side? Even 1–2mm height difference between left and right runners causes binding.

Can I retrofit soft-close to existing non-soft-close hinges?

Yes — Blum makes an 'add-on Blumotion' damper that clips onto an existing Clip Top mounting plate and adds soft-close to the closing cycle. This works on all Blum Clip Top plates (standard, direct mounting, and Expando). The add-on damper does not require replacing the hinge — it mounts onto the plate and provides a cushioned stop. Note: the Blumotion add-on works for closing only; it does not add the full soft-close speed control of an integral Blumotion hinge.

Regulations & Standards

• BS EN 15570 — kitchen furniture; specification for built-in furniture (includes door and drawer mechanism load requirements)

• BS 6222 — domestic kitchen equipment; design and dimensional requirements

• FIRA (Furniture Industry Research Association) — durability testing standards for hinges and runners

• Blum Technical Catalogue — complete range with dimensional drawings

• Grass Technical Catalogue — Nexis and Nova Pro specifications

• KBSA Installation Guidance — Kitchen, Bedroom and Bathroom Specialists Association

• Häfele Fitting Catalogue — alternative hinge and runner specifications

• kitchen units installation — base and wall unit installation

• kitchen worktop fitting — worktop installation and adjacent joinery

• kitchen layout — kitchen layout planning and unit configuration