Installing Gas Struts — Mounting Orientation & Fixing Points

August 1, 2026

A gas strut assists the opening of cabinet flaps using compressed nitrogen gas, where the exact mounting orientation and precisely calculated fixing points determine both proper function and the service life of the fitting.

The correct installation of gas struts on furniture flaps requires a technical understanding of leverage and geometry. If a fixing point is placed just a few millimetres away from the ideal position, the opening angle changes drastically, the flap no longer closes flush, or the hinge is overloaded. Installation is much like calibrating a clock mechanism – a one-millimetre deviation at the base noticeably alters the leverage at the edge of the flap.

This guide is aimed at joiners, fitters, and skilled DIY enthusiasts. It covers determining fixing points, the physically correct cylinder orientation, and step-by-step installation. The time required for initial fitting to a cabinet carcass takes around 20 to 30 minutes with precise preparation.

Required Tools and Materials

For professional installation, you will need the following tools to prevent tear-out in chipboard or MDF and to maintain exact measurements:

Cordless drill/driver with torque adjustment
Wood drill bit (typically `2 mm` or `3 mm` for pilot holes)
Suitable screwdriver bits (usually PZ for cross-head or TX for Torx)
Tape measure or precise folding rule
Scribing awl or sharp pencil
Try square
Two gas struts with suitable force (calculated in Newtons)
Wood screws (countersunk, usually `3.5 mm` x `16 mm` or `4 mm` x `16 mm`)

Note on fitting selection: For wide flaps (from approx. `600 mm` wide), two struts – left and right – must be fitted to prevent the front panel from warping.

The Correct Mounting Orientation: Cylinder Upwards or Downwards?

A common error during gas strut installation is incorrect vertical alignment. A gas strut consists of a thick cylinder tube (containing the gas and some oil) and a thin piston rod.

The physically and mechanically correct orientation when the flap is closed is: cylinder tube upwards, piston rod downwards.

The reason for this lies in lubrication. A small quantity of oil is located inside the cylinder. When the cylinder is positioned upwards, the oil pools at the lower seal through which the piston rod glides. This keeps the seal supple, prevents nitrogen gas from escaping, and secures end-position damping upon opening. If the strut is installed upside down, the seal dries out over time, leading to premature pressure loss.

Calculating and Marking Fixing Points

The exact fixing points (A and B) depend on the desired opening angle (typically `75°`, `90°`, or `110°`) as well as the specific stroke of the strut. Every manufacturer provides a technical data sheet or drilling template. If this is missing, the following basic rule applies for standard kitchen wall cabinets and typical flap fittings at a `90°` opening angle:

Fixing Point on the Carcass (Side Panel)

Measurement is taken from the front interior edge of the carcass (excluding the front panel) towards the back, and from the top interior edge of the carcass (underside of the top panel) downwards.

Dimension X (front to back): Often between `260 mm` and `280 mm`.
Dimension Y (top to bottom): Usually between `240 mm` and `260 mm`.

Fixing Point on the Flap (Front Panel)

Measurement is taken from the top edge of the flap (hinge side) downwards.

Dimension Z: Depending on flap height, frequently at `90 mm` to `110 mm`.
Distance from the side edge: Selected so that the strut runs parallel to the side panel (usually `20 mm` to `25 mm` from the edge).

Before drilling, check the weight of your front panel. For solid oak fronts or thick MDF panels, heavy-duty gas struts with a correspondingly higher N rating (e.g. `350 N` to `500 N`) are suitable.

Step-by-Step Installation Guide

Proceed systematically during installation. The front panel should already be mounted to the carcass using standard concealed cup hinges (usually with a `110°` opening angle).

Step 1: Transfer Measurements and Mark Points

Open the flap and prop it up securely. Use the try square to transfer the measurements from the data sheet onto the inside of the carcass. Mark the drill holes for the mounting brackets. Prick the markings lightly with a scribing awl. This prevents the drill bit from slipping on smooth melamine resin coating.

Step 2: Pre-drilling the Fixing Points

Drill pilot holes at the marked points using a `2 mm` or `3 mm` wood drill bit to a maximum depth of `2 mm` to `3 mm`. Never drill completely through the side panel. Pre-drilling prevents chipboard from splitting when the screws are driven in.

Step 3: Fitting the Mounting Brackets

Screw on the round or elongated mounting plates. Start on the carcass side. Ensure the ball studs of the brackets sit precisely on the measured points. Next, position the brackets on the flap (front panel). Use a cordless screwdriver on a low torque setting to avoid stripping the screw holes. A stripped thread in the wood loses all tensile strength.

Step 4: Clipping in the Strut

Take the strut in hand. Consider the visual appearance of the cabinet interior: for dark interiors, black gas struts are suitable, while white gas struts or silver gas struts work best for lighter kitchens.

Position the cylinder tube on the carcass (top/rear) and the piston rod on the front panel (bottom/front). Push the strut socket ends firmly onto the ball studs of the mounting plates until they audibly click into place. On some models, a small metal retaining clip must first be gently prised open with a flathead screwdriver.

Step 5: Functional Check

Remove the flap support. Close the flap slowly, checking for any resistance. The flap should close softly in the final third of travel (provided the hinges have integrated soft-close damping) and open automatically from an angle of approx. `30°`. If the flap opens too aggressively, the Newton rating selected is too high. If it does not close completely flush, the fixing points are not positioned accurately.

Common Installation Mistakes

Even experienced installers occasionally make errors with the geometry of flap fittings. Avoid the following scenarios:

Only one strut on wide fronts: If only a single strut is fitted to a flap `800 mm` in width, the front panel will twist when closing. The gap reveal becomes uneven, and over time the hinge on the unassisted side will be torn out of the carcass. Always use two struts from a width of `600 mm` upwards.
Incorrect Newton rating: An underpowered gas strut will not hold the flap open (it will drop down). An overpowered strut requires excessive effort to close and pushes the flap slightly away from the carcass when closed, placing excessive stress on the hinges.
Ignoring hinge geometry: The strut always operates in combination with the concealed hinges. If the hinges have a maximum opening angle of `95°` but you align the strut for `110°`, the hinge will be forced open beyond its limit on every operation and will break sooner or later.

FAQ – Frequently Asked Questions About Gas Struts

How do I calculate the required force in Newtons (N)? The rule of thumb is: weight of the flap (including handle) in kg multiplied by `10`. Multiply this result by the flap height in mm and divide by the fixing point distance. Using manufacturer load charts is easier. For example: a standard MDF flap (`600 mm` x `400 mm`) usually requires two struts rated at `250 N` to `320 N` each.

Can a gas strut be adjusted or repaired? No. Gas struts are sealed, pressurised systems. Their force cannot be adjusted. If a strut loses pressure after several years, it must be replaced entirely. However, replacement takes only seconds by simply unhooking the socket ends from the ball studs.

Why does my flap not close flush after fitting? This occurs when dimension X on the carcass has been set too far forward. The strut reaches its fully compressed length (the piston rod is entirely inside the cylinder) before the flap touches the carcass edge. The only solution is to relocate the carcass fixing point a few millimetres towards the rear.

Are there alternatives if cabinet space is too restricted for gas struts? Yes. Where installation depth is very limited, mechanical flap stays with friction braking can be used. These operate via friction rather than gas pressure and are often more compact, though they do not offer the same automatic opening assistance.

Summary of Key Installation Parameters

For a successful installation, keep the key technical points in mind: precise measurement to the millimetre, pre-drilling to protect the substrate material, physically correct alignment (cylinder upwards), and matching the force rating accurately to the front panel weight. With the right tools and precise transfer of geometric data, fitting is a straightforward mechanical process that ensures smooth cabinet operation for years to come.