Internal Drawer as an Alternative to Hettich — Compatible & Matching

An internal drawer is a drawer system concealed behind a cabinet door that structures storage space in base units and is typically mounted via side-mounted or undermount runners in System 32.

When designing kitchens or repairing existing carcases, joiners and fitters often face the question of suitable hardware. When replacing components or upgrading cabinet functionality in an existing kitchen, you are not strictly tied to the original manufacturer. Hardware from furnica can be used as an exact-fit alternative to Hettich, provided technical specifications such as installation width, nominal length, and hole patterns match precisely.

This guide explains the technical criteria to consider when selecting and retrofitting internal drawers to ensure seamless compatibility.

What to Look for Regarding Compatibility

To use a runner as a replacement for Hettich or other established brands, understanding cabinet carcase dimensions is crucial. The furniture industry operates largely on standardised dimensions.

System 32 and the Hole Pattern

The foundation of most modern furniture carcases is System 32. The vertical drill holes in the side panels have an exact spacing of 32 mm from one another. The distance from the front row of holes to the front edge of the carcase is standard at 37 mm. When replacing a runner, check whether the new drawer slides support this grid. If they do, the existing 5 mm drill holes can be reused directly for Euro screws.

Internal Clear Width vs. External Carcase Dimensions

A common mistake when ordering drawer systems is confusing external and internal dimensions. The internal clear width defines the exact distance between the two inner cabinet walls. For a standard base unit with a 600 mm external width and a chipboard material thickness of 16 mm per side, the internal clear width is exactly 568 mm (600 mm - 32 mm). The fittings must be engineered precisely for this internal dimension to prevent binding.

Runner Types and Mechanics: Matching furnica Components

The runner functions like the chassis of a vehicle: it absorbs the dynamic load of the filled drawer and transfers it safely into the side walls of the carcase. Different mechanisms are used depending on requirements.

Full Extension vs. Single Extension

A single extension runner extends only about 75% out of the cabinet by design. The rear section of the drawer remains inside the carcase, making access to stored items difficult. A drawer runners full extension mechanism allows 100% travel. The drawer extends completely past the front edge of the cabinet. When replacing an old single extension runner, upgrading to a full extension version of the same nominal length is generally straightforward.

Undermount Runners

In modern kitchens, the undermount runner is the standard. The runners are concealed beneath the drawer base. This protects the mechanism from dirt and ensures a clean appearance. Corresponding undermount drawer runners are fully compatible with Hettich carcases when nominal length and load capacity match.

Damping and Opening Mechanisms

Motion support mechanisms must not be mixed during planning.

• Soft-Close: Drawer runners with damping cushion the drawer's momentum over the final centimetres and pull it shut softly and silently.
• Push-to-Open: This mechanism ejects the drawer when pressure is applied to the front and is used for handleless fronts.

Both systems act in physically opposite directions and cannot be combined in the same runner.

Carcase Widths and Nominal Lengths in Kitchen Planning

Internal drawers are generally categorised by the external width of the cabinet. For narrow recesses, such as those for spices or bottles, a kitchen cabinet pull-out 30 cm or kitchen cabinet pull-out 40 cm is suitable.

The standard width for pots, pans, and provisions is the kitchen cabinet pull-out 60 cm. Intermediate sizes like the kitchen cabinet pull-out 50 cm are also common.

Alongside width, cabinet depth determines the nominal length of the runner. Lengths typically range from 250 mm - 800 mm. Measure the internal carcase depth. For a depth of 420 mm, choose drawer runners 400 mm. For very shallow bathroom furniture, drawer runners 250 mm are frequently used. The runner should always be roughly 10 mm to 20 mm shorter than the internal carcase depth to avoid collisions with the back panel.

Installation and Retrofitting: Professional Assembly

Retrofitting internal drawers behind an existing hinged door (concealed hinge) requires precision. Note that the door hinges protrude into the carcase. To prevent the internal drawer from colliding with the door hinge during extension, spacer strips must be fitted under the runner on the hinge side, or special inset hinges with an opening angle of 155° or 165° (wide-angle hinges) must be installed to swing the door entirely clear of the internal opening.

Required Tools

• Cordless screwdriver with suitable bits (PZ or TX)
• Marking gauge or cross-line laser
• Bradawl or 5 mm wood drill bit (for Euro screws)
• Folding rule or tape measure

Overview of Assembly Steps

1. Measure and mark: Determine the desired height for the drawer. Use a marking gauge to mark the row of holes parallel to the bottom edge.
2. Drill: If System 32 is not pre-drilled, prepare the fixing points. When using chipboard screws (Ø 3.5 mm or 4 mm), a bradawl is sufficient. For Euro screws, drill a 5 mm diameter hole.
3. Fit runners: Screw the carcase runners in completely level. Maintain the correct setback from the front edge (usually 37 mm).
4. Insert drawer: Place the assembled drawer onto the runners and engage the locking clips until they click audibly.
5. Adjustment: Align the reveal using the tilt and height adjustments on the front locking clips of the undermount runner.

FAQ: Common Questions on Spare Parts and Compatibility

Can I use furnica runners as replacements for Hettich drawers? Yes, furnica runners are suitable for Hettich carcases provided the nominal length (e.g. 450 mm) and mounting style (e.g. undermount runner) match. The fixing points in System 32 are standardised.

How do I replace a faulty gas strut on a Hettich lift-up fitting? When replacing a fitting such as the Hettich Lift-O-Mat, the extension force in Newtons (N) is the critical specification. A strut rated at 380 N, for example, must be replaced with a model featuring the exact same force and identical stroke (extended length).

Which hinge is needed if the internal drawer catches on the door? If the drawer is obstructed by the open door, the existing full overlay hinge (usually 110°) is unsuitable. You will need a replacement wide-angle hinge with a 155° or 165° opening angle. The cup diameter is standard at 35 mm, so no modifications to the door drilling are necessary.

What is the difference between roller runners and ball bearing runners? A roller runner uses nylon rollers and is typically configured as a single extension runner at an entry-level price point. A ball bearing runner uses ball-caged telescopic slides, supports higher load ratings (e.g. 30 kg or 45 kg), and is generally designed as a full extension runner.