Front Extension as an Alternative to Grass — Compatible & Matching

A full-extension runner allows 100% access, whilst a partial-extension runner provides access to roughly 75% of the cabinet interior.

When an existing drawer system in the kitchen jams, the soft-close fails, or a new built-in waste bin needs to be installed, it is time to replace the fittings. Existing kitchen carcasses frequently feature systems from the manufacturer Grass. Anyone wishing to replace components, carry out repairs, or completely reconfigure the cabinet requires fittings that act as an alternative to Grass and fit precisely into the existing hole pattern.

This guide is aimed at fitters and carpenters who need to retrofit or replace a front pull-out. The focus is on the technical requirements, the correct dimensions, and selecting the right mechanism to ensure smooth compatibility with the existing carcass.

Dimensional Requirements and Carcass Compatibility

To ensure a new drawer runner can be fitted into Grass drill holes, the drilling grid inside the cabinet is critical. The industry standard is System 32. This means that holes in a vertical and horizontal line are spaced at an exact distance of 32 mm from each other. The first vertical row of holes standardly begins 37 mm behind the front edge of the carcass.

If the hole pattern of the new runner matches this grid, the system can be secured to the carcass without additional drilling. Fixing is usually carried out using Euro screws with a 5 mm diameter or classic chipboard screws (typically 3.5 mm or 4 mm in diameter).

Alongside the drilling grid, the cabinet width dictates the choice of pull-out. Kitchen base cabinets are standardised. If you are planning a pull-out for a waste sorting system, the design depends on the external dimensions of the cabinet. For narrow recesses, a kitchen cabinet pull-out 40 cm is suitable. If the kitchen offers more room, wider options such as the kitchen cabinet pull-out 50 cm or the kitchen cabinet pull-out 60 cm are used. The nominal length of runners in kitchens is typically 500 mm, whilst for shallower cabinet depths, 400 mm drawer runners are used.

Runner Types: Choosing the Matching Alternative

To restore or enhance kitchen functionality, the mechanism must match the intended application exactly. A front pull-out carrying a heavy wooden front and a fully loaded waste sorting system places high static demands on the hardware.

Runner Position

In modern kitchens originally fitted with Grass, you will mostly find undermount runners. In this system, the runner sits concealed beneath the drawer base. This not only creates a clean look, but also protects the mechanism from dirt falling from above. Anyone looking for a replacement should choose compatible undermount drawer runners that can be screwed into the existing System 32.

Extension Length and Load Capacity

A partial extension is sufficient for shallow cutlery drawers. However, as soon as a waste collector is integrated into the front pull-out, full-extension drawer runners are essential. This is the only way to remove the rearmost bin without catching on the worktop or the upper rail.

Furthermore, pay attention to the weight. A tall front combined with a waste separation system quickly exceeds the standard 30 kg load capacity. In such cases, heavy-duty drawer runners rated for loads of 40 kg, 50 kg, or more are required to prevent the front from dropping when opened.

Motion Technologies: Soft-Close vs. Push-to-Open

When selecting replacement parts, the opening and closing mechanisms must not be confused:

• Soft-Close: A damping system brakes the momentum of the drawer over the final centimetres and pulls it gently and silently into the carcass. If you are looking for a direct replacement for damped systems, you need drawer runners with soft-close.
• Push-to-Open: This mechanism is intended for handleless fronts. Pressure applied to the front activates a spring that pushes the drawer forward a short distance. This is the exact opposite of soft-close damping. You will find corresponding components under push-to-open drawer runners.

Installation and Retrofitting of a Front Pull-Out

Installing compatible drawer systems requires precision. Aligning the front gaps is like adjusting the tracking on a car — a difference of a few millimetres determines smooth running and the overall appearance of the kitchen joints.

Required Tools

• Cordless screwdriver
• Cross-head screwdriver (check for PZ or PH drive)
• Tape measure / folding rule
• Spirit level
• Chipboard screws (e.g. 3.5 mm x 16 mm) or Euro screws

Step-by-Step Installation

1. Removal: Remove the old drawer. Detach the front from the old drawer sides. Unscrew the old carcass runners.
2. Fitting the runners: Position the new carcass runners. Use the existing hole pattern in the carcass. Ensure that the left and right runners sit at the exact same height and depth.
3. Drawer side assembly: If you are replacing the complete box rather than just the runners, assemble the new drawer systems. Here, the back panel and base (usually 16 mm chipboard) are screwed to the metal drawer sides.
4. Front fixing: Screw the new front fixing brackets onto the existing wooden front. Measure the position accurately so that the front sits flush with neighbouring cabinets later.
5. Insertion and adjustment: Clip the drawer onto the runners. Using the adjustment screws on the drawer sides, you can now fine-tune the front in height, side alignment, and often tilt.

Frequently Asked Questions (FAQ)

Can I integrate a built-in waste bin into an existing pull-out? Yes, this is possible provided the internal dimensions of the drawer match the dimensions of the waste bin. It is crucial that the existing runner is a full extension and that the load capacity is sufficient for the additional weight. Pay attention to the external cabinet width — most systems are designed precisely for standard widths.

How do I adjust the damping on runners and hinges? On drawer runners, the damping unit (the cylinder) is usually permanently integrated and cannot be adjusted manually for resistance. If the drawer slams shut, the damper is defective and the runner must be replaced. On a concealed hinge (hinge on the door), some models allow the soft-close mechanism to be activated or deactivated via a small switch on the hinge cup, although the closing force itself is set by the spring.

What must be considered regarding the compatibility of front fixing brackets? Front fixing brackets are manufacturer-specific. A Grass front bracket will not fit into an alternative drawer side. When changing the drawer system, you must unscrew the old front brackets and attach the brackets supplied with the new system to the wooden front. The drilling positions on the front may differ by a few millimetres, which requires new pilot holes (typically pre-drilled at 2 mm for chipboard screws).

Which screws do I use for the carcass runners? If you use the 5 mm holes provided in System 32, Euro screws are used. These have a blunt end and grip perfectly into the pre-drilled holes. If you use smaller, non-through pilot holes, use countersunk chipboard screws, typically sized 3.5 mm x 16 mm or 4 mm x 16 mm.