How to Remove an Old Hinge: Preparing the Right Replacement for Hettich Fittings

The successful removal and replacement of a faulty concealed hinge requires precise identification of the cup diameter, drilling pattern, and overlay type before fitting a compatible replacement.

A worn or defective hinge causes sagging cabinet doors, catching edges, and uneven gaps. Fitters are frequently tasked with removing older hardware, such as fittings from Hettich, and replacing them with compatible new parts. Because the geometry of the hinge arm, cup, and mounting plate must correspond exactly to the drillings in the door and cabinet carcass, systematic removal alongside precise measurement is essential.

This guide is aimed at joiners, carpenters, and experienced installers. It explains the professional removal of old concealed hinges / cabinet hinges, measuring the relevant parameters in millimetres, and preparing the unit for the new fitting.

Difficulty and Time Required

• Difficulty: Intermediate (requires precise measuring)
• Time required: approx. 5 to 10 minutes per hinge
• Personnel: 1 person (a second person is recommended to hold large, heavy doors)

Required Tools & Materials

For damage-free removal and accurate measuring, the following tools are required:

• Cross-head screwdriver (size PZ2 for standard chipboard screws)
• Slotted screwdriver (small, for levering off cover caps)
• Vernier calliper (strictly required for the exact determination of drilling patterns)
• Folding rule or tape measure
• Pencil for marking
• Optional: Wooden dowels (5 mm diameter) and wood glue to repair stripped screw holes

Preparation: Analysing the Existing Setup

Before using your screwdriver, you must analyse the installation setup. This is the only way to ensure you select the correct replacement fitting later. Note the following parameters:

1. Opening angle: How far does the door open? Standard doors generally use fittings around 110 degrees. If you are planning a replacement, you will need concealed hinges / cabinet hinges 110 degrees. Wide-opening doors, such as those for internal drawers, frequently feature concealed hinges / cabinet hinges 165 degrees.
2. Function: Is it a hinge with integrated soft-close damping or an unbuffered variant?
3. Mounting type: Is the hinge arm clipped onto the mounting plate (tool-free assembly) or slid on and secured with a retaining screw (slide-on technique)?

Step-by-Step Guide: Removing the Hinge

Removal involves three logical steps: separating the door from the cabinet carcass, removing the mounting plate, and taking the hinge cup out of the door.

Step 1: Detaching the Cabinet Door from the Carcass

To avoid leverage forces on the remaining screws, always start with the lowest hinge and work your way upwards. On heavy doors, a second person should support the door.

• For clip-on hinges: Reach behind the hinge arm. You will find a release button there. Press it towards the cabinet carcass. The hinge arm will release audibly from the front catch of the mounting plate. Pull the door gently forwards and away.
• For slide-on hinges: Loosen the rear fixing screw on the hinge arm with the PZ2 screwdriver by approximately two to three turns. Do not remove the screw completely. Then slide the hinge arm forwards off the mounting plate.

Step 2: Removing the Mounting Plate

The mounting plate (also referred to as a cruciform or cross mounting plate) remains on the inside of the cabinet carcass initially.

1. Loosen the two fixing screws securing the plate into the carcass. These are often located in the continuous line of drillings known as System 32 (drilling distance is exactly 32 mm, with a distance to the front edge typically of 37 mm).
2. Pull the plate away. If Euro screws are fitted (thick threads, blunt end), retain them provided the thread in the wood is undamaged.

Step 3: Removing the Hinge Cup from the Door

Place the detached door flat on a clean, soft workbench.

1. Flip open the hinge cup cover cap (if present) using a slotted screwdriver.
2. Undo the two fixing screws located to the left and right of the cup.
3. Carefully lever the hinge cup out of the hole. Ease a tight-fitting cup out using gentle levering motions, similar to pulling a tight bearing off a shaft, to prevent chipping the edges of the melamine-faced chipboard.
4. With tool-free cup fittings (e.g. with expanding dowels), a small locking flap on the cup often needs to be flipped up before pulling it out to release the tension on the dowels.

Taking Measurements: Preparing for the Replacement Part

Once the old Hettich hinge has been removed, the most critical phase begins: taking measurements. Make sure to use a vernier calliper. Discrepancies of even a millimetre can prevent the new hinge from fitting.

1. Determining the Cup Diameter

Measure the internal diameter of the large drilled hole in the door.

• The standard for cabinet furniture is 35 mm.
• For lightweight doors (e.g. in bathrooms), mini hinges with a 26 mm cup are occasionally used.

2. Determining the Cup Drilling Pattern

The drilling pattern describes the distance between the two small fixing screws beside the cup. Measure the distance from hole centre to hole centre.

• Hettich traditionally uses the drilling pattern TH 52 (52 mm distance, 5.5 mm offset to the cup centre) or TB 45 (45 mm distance, 9.5 mm offset).
• If the replacement hinge features a different drilling pattern, the old holes must be plugged and new ones drilled.

3. Defining the Overlay Type

The crank (bend) of the hinge arm determines how the door sits on the carcass. Lay the removed hinge on its side and check the shape of the arm:

• Full overlay: The hinge arm is straight (0 mm crank). The door fully covers the edge of the carcass side panel when closed.
• Half overlay (twin overlay): The hinge arm is slightly cranked (usually 9.5 mm crank). Two doors share a single central carcass divider.
• Inset: The hinge arm is heavily cranked (usually 16 mm crank). The door sits flush inside the carcass opening, leaving the edge of the carcass side panel visible.

4. Checking the Cup Drilling Distance (C-Dimension)

The C-dimension is the distance from the edge of the door to the start of the 35 mm cup hole. It typically ranges between 3 mm and 6 mm. This dimension, combined with the mounting plate height, defines the final door reveal gap.

Upgrade Opportunities When Replacing Fittings

If old hardware needs replacing anyway, it is the ideal time to upgrade the functionality of your furniture.

• Switching to soft-close: Loud, slamming doors can be modernised using concealed hinges / cabinet hinges with damping (Soft Close). In modern variants, the damping cylinder is integrated invisibly within the hinge arm.
• Specialist angles: For corner cabinets or bespoke installations, the opening angle must be precisely matched. A 90-degree blind corner cabinet strictly requires concealed hinges / cabinet hinges 90 degrees.
• Comprehensive hardware overhaul: If you are replacing faulty drawer runners alongside hinges, check system compatibility. A complete upgrade to modern drawer systems or replacing worn gas struts with new flap stays and lift-up fittings (paying attention to the rating in Newtons) restores complete functionality across all fittings.

Common Mistakes During Removal and Measuring

1. Using the wrong screwdriver: Using a PH (Phillips) screwdriver on a PZ (Pozidriv) screw inevitably causes cam-out. The screw head strips, making removal difficult. Chipboard screws in furniture hardware almost universally use a PZ drive.
2. Ignoring mounting plate height: Mounting plates are available in different heights (distance D, e.g. 0 mm, 1.5 mm, 3 mm). Combining a new hinge with an incorrect plate height will prevent proper alignment of door reveals.
3. Confusing soft-close with push-to-open: A common misunderstanding during planning. Soft-close gently decelerates and pulls the door shut. Push-to-open ejects the door when the front is pressed. These two mechanisms operate conversely and cannot be combined within a single standard hinge. (The same applies to runners; compare drawer runners push to open).
4. Reusing stripped screw holes: If screws spun freely when removing the old mounting plate (losing thread grip), the new hinge will not hold securely. The hole must be drilled out and plugged with a glued wooden dowel before reinstalling hardware.

Frequently Asked Questions (FAQ)

Can I leave the old Hettich mounting plate in the carcass and only replace the hinge? In most cases, this is not recommended and often technically impossible. Attachment mechanisms (clip geometry or slide-on profiles) vary between different manufacturers and across product generations from the same brand. Always replace the hinge and mounting plate together as a matching set.

How do I repair a stripped 35 mm cup hole in the door? If the cup hole has broken out due to force, metal hinge repair plates can help. These are screwed over the damaged area to provide fresh threaded anchor points for the hinge. Alternatively, clean out the hole using a Forstner bit, glue in a matching timber plug, and drill a fresh 35 mm cup hole.

What should I do if the mounting plate screws no longer grip in the carcass? For stripped 5 mm holes in System 32 drillings, using a threaded insert (such as a Rampa insert) is recommended. This is screwed into the enlarged hole to provide a robust metric internal thread (e.g. M4), allowing the mounting plate to be fastened permanently with a matching machine screw.

How do I determine whether I need full overlay or half overlay hinges? Measure the thickness of the carcass side panel (typically 16 mm or 19 mm). Close the door. If the door completely covers the front edge of the carcass side, you require a full overlay hinge. If the door covers only half the edge (approx. 8-9 mm) to allow room for an adjacent door, you require a half overlay hinge.