Drawer Systems as an Alternative to Grass — Compatible and Fitting
A compatible drawer system requires an exact match of nominal length, internal cabinet width, and the drilling pattern of the runner profiles, typically based on System 32.
When an existing drawer runner fails in the kitchen, bathroom, or office, or when a complete cabinet needs reconfiguring, finding the correct fittings is essential. As a joiner or experienced fitter, you know that you do not necessarily need the exact part from the original manufacturer. High-quality drawer systems from a specialist hardware supplier serve as a fully fledged alternative to Grass and integrate seamlessly into existing carcasses, provided the technical parameters are strictly observed.
This guide covers the technical prerequisites, dimensional specifications, and installation steps required to professionally fit drawer runners and metal drawer box systems as replacements or upgrades.
Key Factors for Compatibility
For a new runner system to fit Grass carcasses or other industrially manufactured furniture units, three core metrics must match: nominal length, internal width, and drilling pattern. The drilling pattern acts as the DNA of the cabinet — if it matches, the new runner fits into the unit without complex modifications.
The Drilling Pattern and System 32
Most modern kitchen cabinets and office furniture are built around System 32. This means:
- The centre-to-centre distance between holes is precisely 32 mm.
- The distance from the front edge of the carcass to the first row of holes is typically 37 mm.
- The standard hole diameter for Euro screws is 5 mm.
When installing runners as an alternative to Grass, check the position of the fixing holes on the cabinet profile. If they align with the 32 mm grid, direct installation using conventional Euro screws is straightforward.
Nominal Length and Installation Depth
The nominal length (NL) defines the depth of the drawer from the back panel to the inside face of the front. It dictates the required length of the runner. Standard dimensions in kitchen applications range between 400 mm and 550 mm. The internal carcass depth must equal at least the nominal length of the runner plus a clearance tolerance of roughly 3 mm to 5 mm. For instance, when fitting drawer runners 400 mm, the cabinet interior must measure at least 405 mm deep.
Internal Cabinet Width and Material Thickness
When selecting complete drawer box systems (drawers with double-walled metal sides), the width of the base and back panel is calculated from the internal cabinet width and the side panel thickness (usually 16 mm or 19 mm). For wooden drawers mounted on concealed runners, the exact installation width of the runners must be deducted from the internal cabinet dimension to determine the external width of the timber drawer box.
Suitable Drawer Systems and Runner Types
Depending on the area of application and load weight, different mechanical concepts are available that are fully compatible with Grass drilling patterns in standard carcasses.
Concealed Undermount Runners for Wooden Drawers
When working with classic timber drawers, concealed runners are the preferred choice. Undermount drawer runners are fitted underneath the drawer base. The drawer sits directly on the runner and locks into place at the front via dedicated locking clips. This mechanism allows tool-free height and tilt adjustment directly at the clip. A full extension runner pulls out 100%, making it significantly easier to access items stored right at the back of kitchen units.
Drawer Box Systems for Kitchens
A modern kitchen drawer system usually consists of a runner profile and a double-walled steel side panel. These systems are ideal when replacing an entire drawer assembly. Pre-configured solutions exist for standard unit sizes. A 60 cm kitchen cabinet pull-out requires specific base and back panel widths cut precisely according to the runner system specifications.
Mechanical Functions: Soft-Close vs. Push-to-Open
When selecting runner mechanisms, a clear distinction must be made between two distinct modes of operation:
- Soft-Close: An integrated hydraulic or spring damper cushions the closing action and gently pulls the drawer fully shut over the final few centimetres. Drawer runners with soft close are the standard in modern kitchens.
- Push-to-Open: Designed specifically for handleless fronts. Pressing the front releases a spring or magnetic catch, causing the drawer to pop open slightly. Push to open drawer runners do not feature a self-closing mechanism, as this would counteract the ejection mechanism.
Both types are available as full extension drawer runners, but their mechanisms cannot be combined or mixed on the same drawer unit.
Installation and Retrofitting: Step by Step
Replacing drawer runners or carrying out a complete new installation requires precision. The following steps guide fitters through installing an alternative to Grass into an existing carcass.
Required Tools
- Cordless drill/driver
- Screwdriver with PZ (Pozidriv) or TX (Torx) drive
- Folding rule or tape measure
- Spirit level or try square
- Bradawl
- Chipboard screws (Ø 3.5 mm or 4 mm) or Euro screws (Ø 5 mm)
1. Removal and Preparation
Remove the old drawer. For undermount runners, release the front locking clips under the drawer base. Unscrew the old cabinet runners. Inspect the existing hole pattern. If the 32 mm hole line is intact, these holes can be reused directly for the new system.
2. Installing the Cabinet Runners
Position the new carcass runner. The front fixing screw is usually located 37 mm from the front edge of the cabinet. Ensure precise horizontal alignment. For pre-drilled carcasses, use Euro screws (Ø 5 mm), as these provide the greatest pull-out resistance in System 32. For un-drilled carcasses, use countersunk chipboard screws (Ø 4 mm) to prevent the screw heads from catching on the runner rollers or ball cages.
3. Drawer Preparation
For metal drawer box systems, screw the front fixing brackets to the cabinet front panel and clip them into the drawer sides. For wooden drawers with undermount runners, mount the locking clips flush against the front inside corners of the drawer bottom.
4. Insertion and Adjustment
Place the drawer onto the runners and push backwards with gentle pressure until the locking clips engage with an audible click. Next, carry out fine adjustments. Modern systems offer 3-dimensional adjustment:
- Height adjustment: Via a thumbwheel on the locking clip (typically +/- 2 mm).
- Side adjustment: To align the reveal gaps between fronts (typically +/- 1.5 mm).
- Tilt adjustment: At the rear panel or rear gallery rail to correct forward tilting on deep, high-sided drawers.
Frequently Asked Questions (FAQ)
Can I fit Grass drawer boxes onto runners from other manufacturers? Generally, no. The runner profiles and the engagement mechanisms on the metal sides or wooden drawer clips are proprietary to each manufacturer. It is always recommended to replace the entire system — both the cabinet runners and the drawer sides or locking clips. A complete replacement system from a hardware specialist will fit the carcass perfectly, provided the nominal length and drilling pattern match.
What load capacity is required for kitchen drawers? For standard cutlery drawers, a dynamic load rating of 30 kg is sufficient. For deep pan drawers or larder pull-outs, opt for runners rated between 40 kg and 50 kg. For heavy-duty applications, such as storing crates or heavy equipment, select heavy duty drawer runners with a load capacity of up to 80 kg or more.
What is the difference between roller runners and ball bearing runners? A roller runner operates on nylon wheels and is usually designed as a single extension (partial extension). It is cost-effective and practical, though it offers less lateral stability. A ball bearing runner uses steel ball bearings housed in telescopic steel profiles, mounts to the side of the drawer box, and delivers high load capacities with smooth full extension.
Why is my soft-close drawer not closing completely? This commonly occurs if the carcass is out of square or if the cabinet runners have been fitted under tension. Measure the internal width at both the front and back of the cabinet — these must be identical to the millimetre. Overloading the drawer beyond its specified load capacity in kg can also prevent the damper unit from functioning properly.