Mounting Plate H0, H2 or H3? Calculating Door Overlay and Reveal

The spacer height of a mounting plate (H0, H2, H3) regulates the overlay of a cabinet door and balances the gap to the carcase with millimetre precision. When constructing cabinet furniture, choosing the correct concealed hinge alone is not enough. The counterpart on the cabinet carcase – the mounting plate (also known as a cross mounting plate) – plays a decisive role in how the door rests on the carcase side when closed and whether sufficient clearance remains for movement during opening.

This guide is aimed at joiners, fitters, and ambitious cabinetmakers who need to calculate door overlays accurately and specify the correct fittings for their project.

Key Purchasing Criteria for Mounting Plates and Hinges

To determine the correct mounting plate, the hinge dimensions, material thicknesses, and required gap pattern must be precisely coordinated. The following technical parameters must be observed:

• Cup diameter: The industry standard for the drilled hole in the cabinet door is 35 mm. For very narrow frames or small doors, mini hinges with 26 mm are available. Concealed hinges 35 mm form the foundation for almost all common furniture designs.
• Drilling pattern and hole lines: Professional furniture fittings are based on the System 32 standard. The fixing holes of the mounting plate are spaced 32 mm apart. The front hole is positioned exactly 37 mm from the front edge of the carcase.
• Cup distance (C-dimension): This is the distance from the door edge to the edge of the 35 mm hole. It typically varies between 3 mm - 7 mm depending on the hinge type and manufacturer. The C-dimension directly influences the overlay.
• Minimum reveal: Every door requires a side gap to prevent rubbing against the adjacent door or carcase side when swinging open. The minimum reveal depends on door thickness and opening angle.

Types and Options at a Glance: Understanding Overlay Applications

The height of the mounting plate can only be calculated in combination with the hinge crank. The crank describes the bend in the hinge arm. Depending on the position of the door relative to the carcase, three basic application types are distinguished:

1. Full Overlay (Surface-Mounted Door)

With a full overlay, the closed cabinet door rests almost entirely on the front edge of the carcase side panel. The hinge arm is straight (0 mm crank). This construction is used for single carcases or the outer sides of cabinet runs. To achieve maximum overlay, a mounting plate with a spacer height of 0 mm (H0) is almost always used here. Matching fittings: Full overlay concealed hinges.

2. Half Overlay (Twin / Shared Gable Application)

When two doors close onto a single central partition (typically 16 mm - 19 mm thick), this is called a half overlay. The hinge arm has a pronounced bend (approx. 9.5 mm crank), which halves the overlay. Both doors cover slightly less than half of the central panel each, leaving a reveal between them. Matching fittings: Half overlay concealed hinges.

3. Inset Application (Inset Door)

With an inset application, the door does not rest on the face of the carcase, but sits flush between the carcase panels. The hinge arm has an extreme crank (usually 16 mm). Here, calculating the gap is especially critical so that the door does not bind against the inside of the carcase wall during opening. Matching fittings: Inset concealed hinges.

Which Size for Which Case? Calculating Overlay and Plate Height

The interaction between hinge cranking and the mounting plate works like a gear system: change one component, and the entire mechanism shifts. The height of the mounting plate (D-dimension) is used to reduce the overlay (A-dimension) of the door.

The fundamental rule is: The higher the mounting plate, the smaller the overlay of the door onto the carcase.

The mathematical formula for the overlay on a standard hinge is (simplified depending on manufacturer constants): Overlay = Base constant + Cup distance - Mounting plate height

Example for a full overlay with a base constant of 11 mm:

• You drill the hinge cup with a 5 mm distance to the edge.
• You use an H0 (0 mm) mounting plate.
• Calculation: 11 mm + 5 mm - 0 mm = 16 mm overlay.

If your carcase side panel is 16 mm thick, the door will now cover it completely (0 mm gap to the edge). However, if you require a 2 mm reveal to a neighbouring door, the overlay must be only 14 mm.

How do you achieve this? Either reduce the cup distance during drilling to 3 mm (11 + 3 - 0 = 14 mm), or – what is far more common in practice if holes are already drilled – swap the mounting plate:

• Select an H2 (2 mm) mounting plate.
• Calculation: 11 mm + 5 mm - 2 mm = 14 mm overlay.

When to Choose H0, H2 or H3?

• H0 (0 mm): The absolute standard for carcase panels with 16 mm - 19 mm thickness in full overlay applications. Delivers maximum door coverage.
• H2 (2 mm): Used to reduce the overlay by 2 mm. Often necessary with thicker carcase sides (e.g. 22 mm), when wider reveal patterns are required, or to prevent collisions on profiled doors.
• H3 / H4 (3 mm / 4 mm): Specific problem solvers. Frequently used for special angled cabinet designs or when the reveal needs to be significantly increased in inset applications.

Regardless of the application type, opening angles also determine the kinematics. A standard cabinet usually requires concealed / cabinet hinges 110 degrees. For carcase units with internal drawers, wide-angle hinges with 155° are mandatory so that the open door does not obstruct the runner path.

Installation Notes: Fitting the Mounting Plate Correctly

Installation requires precision. Even hinges with 3D adjustment can only compensate for minor drilling inaccuracies.

Tools Required:

• Cordless drill/driver
• Forstner bit (35 mm)
• Wood drill bit (5 mm for Euro screws or 3 mm pilot drill for wood screws)
• Screwdriver (PZ or TX)
• Marking awl and try square

Step-by-Step Procedure:

1. Marking out: Mark the position of the mounting plate on the inside of the carcase. The front row of holes sits exactly 37 mm from the front edge. The vertical distance between drilling centres is 32 mm.
2. Drilling: Drill the 5 mm holes for system screws (Euro screws). When using classic 3.5 mm countersunk chipboard screws, light pilot drilling or centre punching is sufficient.
3. Drilling the hinge cup: Drill the 35 mm hole into the door. Pay close attention to the correct cup distance (e.g. 4 mm from the edge) and drilling depth (usually 11.5 mm - 12.5 mm) so that the point of the Forstner bit does not pierce through the front face.
4. Fastening: Screw the mounting plate to the carcase and the hinge cup into the door.
5. Clipping on and adjusting: Modern concealed / cabinet hinges feature a clip-on mechanism. Press the door onto the mounting plate without tools until it audibly clicks into place. Then carry out fine adjustment (height, side, depth) using the adjustment screws on the hinge arm.

FAQ – Frequently Asked Questions about Mounting Plates and Overlay

What does H0 mean on a mounting plate? The designation H0 (or D0) indicates that the mounting plate has a spacer height of 0 mm. It adds no extra height and, when combined with the hinge, delivers the maximum overlay of the door onto the carcase.

Which mounting plate do I need for an inset door? For an inset application, a high-crank hinge (usually 16 mm crank) is required. The mounting plate is typically a standard H0 plate, but within System 32 it must be set back by the door thickness plus the reveal (e.g. 37 mm + 19 mm door thickness + 2 mm reveal = 58 mm from the front edge).

Can I adjust the overlay without replacing the mounting plate? Yes, within a limited range. Almost every modern concealed hinge includes a lateral adjustment screw on the hinge arm. This allows seamless overlay adjustment – usually within a range of +2 mm to -2 mm. If this adjustment range is insufficient, a mounting plate with a different height must be used.

Are mounting plates from different manufacturers compatible? No. Although the drilling pattern on the carcase (System 32) is standardised, the clip-on or slide-on mechanism varies significantly between manufacturers (and often between different product lines from the same brand). The hinge and mounting plate must always come from the same system.

What is the difference between soft-close and push-to-open? Soft-close is an integrated damping mechanism that cushions the closing door. Concealed / cabinet hinges with damping (soft close) pull the door closed smoothly and quietly. Push-to-open (tip-on) is the opposite mechanism for handleless fronts: pressing the door releases a spring-loaded catch to pop it open. Push-to-open requires specialised hinges without self-closing action (unsprung).