Bi-Fold Corner Kitchen Cabinet Hinges: Replacement Fittings for Blum and Hettich

A bi-fold hinge system for a corner kitchen cabinet typically combines a 165° wide-angle hinge on the cabinet carcase with a 135° specialised hinge connecting the two door leaves.

Corner kitchen units are subjected to continuous mechanical stress. When a bi-fold door starts to sag, scrape, or pull out from the wood, worn fittings are almost always the cause. Fitters and seasoned DIYers are then faced with sourcing the correct replacement. It is not strictly necessary to purchase expensive original parts from brands such as Blum or Hettich. As long as technical parameters such as cup diameter, drilling pattern, and opening angle match precisely, alternative concealed hinges can be installed and adjusted without issue.

This guide explains the technical specifications of corner cabinet hinges to help you select the exact fittings needed for your repair or new assembly.

Key Buying Criteria for Replacement Hinges

To replace a broken hinge, exact measurements must be taken from the cabinet. A hinge is only compatible if the drillings in the timber match the geometry of the fitting.

• Cup diameter: The most critical measurement is the hole drilled into the door where the hinge cup is recessed. The industry standard is 35 mm. Smaller 26 mm variants are virtually never found on heavy kitchen doors. The cup depth is normally 11.5 mm.
• Drilling pattern (hole centres): This refers to the distance between the two fixing screws adjacent to the hinge cup. Common centre-to-centre spacings are 45 mm, 48 mm, or 52 mm. Measure this from the centre of one hole to the centre of the other.
• Crank / overlay type: The crank defines how the door sits relative to the carcase when closed. For the main door of a corner unit attached directly to the cabinet side, a full overlay fitting is almost always required (the door fully covers the edge of the carcase wall).
• Mounting plate: The cruciform mounting plate (often called a base plate) attaches the hinge arm to the internal carcase wall. It is usually secured using System 32, meaning the fixing hole spacing is exactly 32 mm. The plate thickness/height (e.g. 0 mm or 3 mm) regulates the clearance between the door and carcase.

The Interaction of Angles on a Corner Cabinet

A classic bi-fold door on an L-shaped corner unit (often combined with a carousel) operates like a mechanical knee joint. To fold the doors completely clear of the opening, two distinct hinge types work in series.

1. The Carcase Hinge (Wide-Angle Hinge)

The first door leaf is mounted to the side wall of the cabinet. This requires a hinge with a very wide opening angle to swing the door fully out of the way. Standard specifications use 155° or 165° fittings. A standard 110° hinge would severely obstruct access to the cabinet interior.

2. The Leaf-to-Leaf Hinge (Bi-Fold Hinge)

The second door leaf is not fixed to the carcase, but directly to the first door panel. This requires a specialised bi-fold hinge with a typical opening angle of 135°. This fitting ensures both panels fold together upon opening and form a neat 90° corner when closed.

Special Case: The Diagonal Corner Cabinet

Not every corner unit uses a bi-fold door. Cabinets with a single angled front (where the door sits at a 45° angle relative to adjacent cabinets) require an entirely different fitting. In this scenario, a 45° angled hinge is used to accommodate the angled carcase geometry.

Which Hinge for Which Application?

Choosing the correct fitting depends entirely on its position on the cabinet and the geometry of the door front.

• When the door is mounted directly to the carcase side and must swing wide open: Choose a 165° hinge with a full overlay.
• When connecting two folding door leaves together: Choose a 135° bi-fold hinge.
• When the cabinet has a single diagonal front panel: Choose a 45° hinge.
• When doors must close softly and quietly: Look for models with integrated soft close. An integrated hydraulic damper slows the door during the final centimetres of travel. Note: On bi-fold systems, it is generally sufficient to have soft close only on the 165° carcase hinge; the 135° intermediate hinge does not strictly require its own damper.

Installation and Adjustment on a Corner Kitchen Unit

Replacing a hinge demands precision, but can be completed with standard tools. You will need a cordless screwdriver, a PZ2 Pozidriv screwdriver, and a tape measure.

1. Removal: Release the door using the clip-on mechanism on the mounting plate. Then unscrew the hinge cup from the chipboard or MDF of the door panel.
2. Inspection: Measure the cup hole. If the diameter is exactly 35 mm, a standard replacement hinge will fit into the existing recess.
3. Fitting: Insert the new hinge cup and screw it in place square to the door edge. If screw holes are stripped, use specialised repair plates or reinforce the holes beforehand with wooden dowels.
4. Adjustment: Modern concealed hinges feature 3D adjustment. Using the adjustment screws on the hinge arm, the door can be adjusted for height, depth (gap to carcase), and lateral overlay (gap alignment) within a range of +/- 2 mm. Align the bi-fold door so that it sits parallel to neighbouring doors when closed, without rubbing.

Tip for internal storage: If you are upgrading your corner unit during hinge maintenance, check the clearance of internal pull-outs. A modern full-extension corner pull-out unit makes optimal use of blind corner space. Ensure your wide-angle hinges offer zero protrusion so they do not obstruct the travel path of internal wirework or shelves.

FAQ: Frequently Asked Questions About Corner Cabinet Hinges

Can I replace a Blum or Hettich hinge with an alternative brand? Yes. As long as the cup diameter (typically 35 mm) and overlay type match, alternative brands can be used. However, always replace both the hinge and its matching mounting plate together, as clip systems between different manufacturers are not interchangeable.

Why does my bi-fold door fail to close flush and stick out? This is usually caused by incorrect depth or lateral adjustment. Use the adjustment screws on the 165° hinge arm to draw the door closer to the carcase. Also check that the mounting plate is securely fastened into the System 32 line holes.

Do I need a 135° hinge for a diagonal corner cabinet? No. A 135° hinge is designed solely for joining two folding door panels. A cabinet with a single continuous door set at a 45-degree angle requires a dedicated 45° angled hinge.

What screws should I use for fixing? Use standard countersunk chipboard screws with a Pozidriv (PZ) drive. For securing the hinge cup into the door, screws with a diameter of 3.5 mm or 4 mm and a length of 15 mm to 17 mm are ideal.

Matching Fittings for Your Project

To find the correct components for your corner cabinet or furniture project, browse the technical specifications in our range:

• Overview of all models: Concealed Hinges / Cabinet Hinges
• The standard for kitchen doors: Concealed Hinges / Cabinet Hinges 35 mm
• For doors overlaying the carcase side: Full Overlay Concealed Hinges
• For wide opening angles (carcase hinge on bi-fold doors): Concealed Hinges / Cabinet Hinges 165 Degree
• For connecting bi-fold door leaves: Concealed Hinges / Cabinet Hinges 135 Degree
• For diagonal corner cabinets: Concealed Hinges / Cabinet Hinges 45 Degree
• For smooth, silent closing: Concealed Hinges / Cabinet Hinges with Soft Close