Full Extension Drawer Runners: Robust Replacements for Hettich Slides
A full extension runner allows the drawer to be pulled out 100% from the cabinet carcass, whereas a partial extension stops at around 75%.
When a drawer jams, scrapes, or blocks when pulled out, the issue is almost always due to the runner. In many fitted kitchens and workshop cabinets, Hettich runners are installed at the factory. These perform well over years, but are subject to mechanical wear and tear under daily use. When the first steel balls dislodge from the cage or the running profile is bent, opening the drawer feels like sand in the mechanism. In this scenario, a replacement is unavoidable.
Switching to new drawer runners full extension is a lasting solution to restore the full functionality of the furniture.
Causes of Wear and Tear on Drawer Runners
Mechanical components have a defined service life and maximum load limits. The following factors lead to runner failure:
- Overloading: Every runner has a specific dynamic load capacity in kilograms. If this is permanently exceeded, the metal profile of the ball bearing runner deforms or the plastic of the rollers breaks.
- Contamination: Dust, grease, and small particles settle in the grease of the ball bearings. The balls seize up and grind grooves into the running track profile.
- Lack of parallelism: If the carcass is not square or the runners were screwed in with tolerances during initial assembly, the extension will twist. This leads to one-sided abrasion.
When to Replace and Which Spare Part Fits?
A replacement is due when the drawer can only be moved with significant effort, a distinct grinding noise is audible, or the self-closing mechanism is defective.
To find the matching replacement part, you must measure the existing system accurately. The nominal length of the runner depends on the depth of the drawer box, not on the depth of the cabinet carcass. Common lengths in furniture construction are 400 mm, 500 mm, and 600 mm. For example, if you have a 500 mm deep drawer box, you need exactly drawer runners 500 mm.
In addition, the design type must be identified. Is it a side-mounted ball bearing runner or concealed under-mount drawer runners screwed beneath the drawer bottom? The installation gap (the clearance between the drawer box and the carcass wall) is typically 12.7 mm for side ball bearing runners.
Tools Required for the Replacement
To dismantle the old drawer runners and install the new system, you will require the following tools:
- Cordless screwdriver
- PZ2 bit (Pozidriv) or TX20 bit (Torx) for chipboard screws
- Folding rule or tape measure
- Joiner's square
- Bradawl for pre-marking screw holes
- If necessary, Euro screws (Ø 6.3 mm) if the carcass drillings in the System 32 are worn out
Step-by-Step Solution: Installing the Full Extension Runner
The following guide covers the replacement of a side-mounted telescopic runner.
1. Dismantling the Old System
Pull the drawer out completely. On most runners, there is a small plastic release lever on the rail. Push this up or down to release the drawer from the carcass member. Remove the drawer. Then unscrew the old runner parts from both the carcass and the drawer box.
2. Checking Measurements and Preparation
Check the hole pattern in the cabinet. Industrially manufactured furniture uses System 32, where the drillings are spaced 32 mm apart. The new runners feature slotted holes tailored precisely to this hole grid.
3. Installing the Carcass Runner
Separate the inner runner profile (which attaches to the drawer) from the outer profile (which attaches to the carcass). Position the outer profile against the inside carcass wall. Use the joiner's square to ensure that the runner is completely horizontal. Fasten the runner through the vertical slotted holes – this leaves you with 1 mm to 2 mm of leeway for height adjustment later.
4. Installing the Drawer Runner
Fasten the inner profile flush with the bottom edge of the drawer side. Complete parallelism is essential here as well.
5. Inserting and Adjusting
Guide the drawer with the fitted inner profiles into the carcass runners. Push the drawer backwards with light, even pressure until the catch audibly engages. Check the running action. If you have installed drawer runners with soft close, the drawer should decelerate gently over the final few centimetres and pull itself closed automatically.
Special Cases: Heavy Loads and Long Extensions
For workshop trolleys, large kitchen pantry units, or deep plinth drawers, standard runners are insufficient. Substantial leverage forces act here. In such cases, switching to heavy duty drawer runners is advisable. These runners are manufactured from thicker material (often 2.0 mm to 2.5 mm steel sheet) and feature more robust ball cages.
The load capacity for these models is usually rated in classes such as 45 kg, 80 kg, or even over 100 kg. With long lengths, such as drawer runners 600 mm, ensure without fail that the cabinet carcass is secured against tilting (anti-tip wall bracket fixed to the wall), as the centre of gravity shifts far forward when fully extended.
Preventing Recurrent Wear
To maximise the service life of the new hardware, observe the following technical parameters:
- Observe the weight limit: Calculate the self-weight of the drawer plus the weight of the contents.
- Align the carcass: Use a spirit level to verify that the cabinet is plumb. A crooked carcass causes torsional stress on the runners.
- Cleaning: Clean dust from the running tracks regularly with a dry cloth. Do not use aggressive solvents, as these wash away the factory-applied lubricating grease from the ball bearings.
FAQ – Frequently Asked Questions About Repairs
Can I replace a roller runner with a ball bearing full extension runner? Yes, this is mechanically possible provided the installation clearance between the drawer and the carcass wall matches. For most roller drawer runners, the gap is 12.5 mm, which is compatible with standard ball bearing runners (12.7 mm). However, you will need to drill new fixing holes.
Can I combine soft-close and push-to-open on one runner? No, these are conflicting mechanisms. A soft-close slows the drawer down and pulls it shut. A push-to-open drawer runners system requires a mechanical pressure point to release a tensioned spring that pushes the drawer open. Both systems block each other.
How do I measure the correct replacement length? Measure the outer edge of the drawer side from the back panel to the inside face of the drawer front. If the measurement is 400 mm, choose drawer runners 400 mm. The carcass depth merely needs to be at least 3 mm to 5 mm deeper than the runner to accommodate it.
Selecting the Right Replacement Part
Choosing the correct runner depends on precise dimensions and the desired operating comfort. Check the installation clearance, measure the drawer box depth in millimetres, and decide whether you require a standard load capacity of 30 kg or a heavy-duty variant. Once these parameters are established, you can specify the mechanically suitable runner fittings for your furniture.