Hinges are categorized into Full Overlay (Straight Arm), Half Overlay (Crank/Bend Arm), and Inset (Large Bend Arm) to match different coverage relationships between the door panel and the side panel (Full Overlay / Half Overlay / Inset), ensuring accurate door closing positions and preventing operational interference.
1. What are Full Overlay, Half Overlay, and Inset Hinges?
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Full Overlay (Straight Arm): The hinge arm has almost no bend. When closed, the door panel completely covers the side panel, making the side panel invisible. Suitable for standalone cabinets or single doors covering the entire cabinet opening.
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Half Overlay (Half Crank / Medium Bend Arm): The hinge arm has a moderate bend. When closed, the door panel covers half of the side panel. When two adjacent doors share the same side panel, each covers half. Suitable for double-door cabinets sharing a central divider.
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Inset (Large Crank / Full Bend Arm): The hinge arm has a pronounced bend. When closed, the door panel sits inside the cabinet side panels (flush mount), leaving the side panels fully exposed. Suitable for designs where door panels are embedded inside the cabinet frame.
2. Application Scenarios
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Full Overlay (Straight Arm) Application: This is the most common type, suitable for standalone cabinets where only one door is mounted on a side panel—for example, single-door wardrobes, independent storage cabinets, and bookcases. Its advantage is a clean appearance after installation with no visible cabinet frame.
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Half Overlay (Medium Bend) Application: Designed specifically for configurations where two doors share a single central side panel. Commonly used in double-door wardrobes, kitchen cabinets, or side-by-side bookcases. It ensures both doors open and close smoothly while neatly covering a portion of the side panel without leaving unsightly gaps or causing door collision.
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Inset (Large Bend) Application: Primarily used in designs pursuing extreme minimalism and concealed effects. Used when the door panel needs to be fully embedded within the cabinet frame, such as mirror-faced invisible cabinets, hidden storage room doors, or integrated refrigerator/oven housing units. It achieves a flush finish between the cabinet door and the cabinet body.
3. How to Calculate Door Dimensions?
Calculations require first defining the net cabinet width, number of door panels, hinge combination type, dan reserved gaps (typically 2–3 mm per vertical gap, and 2–4 mm total for top/bottom gaps).
3.1. Width Calculation Formula
$$\text{Single Door Width} = \frac{\text{Effective Calculation Width} – (\text{Number of Gaps} \times \text{Single Gap Width})}{\text{Number of Doors}}$$
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Determining Effective Calculation Width:
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All Full Overlay: Use the total exterior cabinet width (including both side panels).
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Including Half Overlay: Use the interior net cabinet width + total thickness of covered side panels (typically counting each shared panel once; e.g., if two doors share one 18 mm panel, add 18 mm).
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All Inset: Use the interior net cabinet width (excluding side panels).
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Gap Number Rules:
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Overlay Doors (Full/Half Overlay): Number of Gaps = Number of Doors – 1 (gaps between doors).
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Inset Doors: Number of Gaps = Number of Doors + 1 (gaps between doors + gaps between doors and interior cabinet side walls).
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Example: Interior net cabinet width is 800 mm, making a 2-door opening sharing one 18 mm side panel (using Half Overlay hinges), with 3 mm reserved gaps.$$\text{Effective Width} = 800 + 18 = 818\text{ mm}$$$$\text{Number of Gaps} = 1$$$$\text{Single Door Width} = \frac{818 – 3}{2} = 407.5\text{ mm}$$
3.2. Height Calculation Formula
$$\text{Single Door Height} = \text{Interior Cabinet Height} – \text{Total Top and Bottom Gaps}$$
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Reserved top and bottom gaps typically total 2 mm to 4 mm (1–2 mm top gap, 1–2 mm bottom gap, adjusted based on floor levelness).
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Example: Interior cabinet height is 2000 mm, reserving a total of 3 mm top and bottom gaps:$$\text{Door Height} = 2000 – 3 = 1997\text{ mm}$$
Key Considerations
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Board Thickness Baseline: The “Full Overlay / Half Overlay” values above are based on standard 18 mm thick side panels. If side panel thickness varies (e.g., 16 mm or 25 mm), coverage expectations must be adjusted proportionally, though the hinge selection logic remains unchanged.
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Measurement Sequence: Determine the hinge layout first (where to use Full, Half, or Inset), then measure net dimensions of corresponding sections for addition/subtraction. Never simply divide total exterior cabinet width by the number of doors.
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Adjustment Allowance: Subtract an extra 0.5–1 mm during panel cutting as a fine-tuning allowance. While hinges offer 3D adjustment capabilities, excessive dimensional errors cannot be compensated for by hardware adjustment alone.
4. How to Determine the Number of Hinges Required?
The core metric for determining hinge quantity is door panel height, adjusted for door weight and material. Hinges are typically specified in height tiers; add 1 additional hinge for every 600–800 mm increase in height or for significant weight increases.
Standard Configuration Guidelines (By Door Panel Height)
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$ ≤ $ 800 mm: 2 hinges
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800 mm – 1500 mm: 3 hinges
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1500 mm – 2200 mm: 4 hinges
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2200 mm – 2500 mm: 5 hinges
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> 2500 mm: 6 or more hinges (requires engineering calculation)
Special Cases Requiring Extra Hinges
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Heavy Door Panels: For dense materials like solid wood, sintered stone, or glass, add 1 extra hinge if a single panel weighs $>10\text{ kg}$, even if the height is within standard limits.
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High-Frequency Usage: In kitchens or commercial/public spaces with frequent daily operation, add 1 extra hinge beyond standard to extend service life.
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Overwide / Overthick Doors: If door width $>600\text{ mm}$ or thickness $>25\text{ mm}$, the torque increases; additional support is required to prevent sagging.
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Mounting Positions: Top and bottom hinges are usually placed 100–150 mm from door edges, with middle hinges spaced evenly to avoid interference with shelves or pull handles.
Installation Distribution Principles
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The top hinge should be approx. 100–150 mm from the top of the door.
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The bottom hinge should be approx. 100–150 mm from the bottom of the door.
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Intermediate hinges must be spaced equidistantly to ensure even load distribution.
When selecting hinges in practice, measure the net height and estimated weight of the door panel first against these guidelines. For specialized door panels (e.g., custom shapes, oversized, or extra heavy)。