Gas spring end fittings connect gas springs or traction gas springs to the mounting points of a flap, bonnet or other movable structure. They are screwed onto the connection thread of the gas spring and, depending on the design, provide a rigid, pivoting or angle-compensating connection.

Febrotec offers end fittings for various connection threads, particularly M4, M6, M8 and M10. The range includes ball joints, ball sockets, clevis ends, eye ends, spherical bearing ends, extensions and axial joints made from different materials.

The end fitting influences the overall installation length, freedom of movement and load transfer of the complete gas spring. It should therefore be selected not only by thread size, but also by connection type, dimensions and the movement required in the application.

Which End Fitting Is the Right Choice?

Type	Design and Application
Type 1 – Ball joint	Complete articulated connection consisting of a ball socket and ball stud. It allows angular movement in several directions and is particularly suitable for movable flaps, lids and bonnets.
Type 2 – Ball socket	End fitting designed to snap onto a matching ball stud. It compensates for minor angular misalignment and allows quick installation. The ball diameter must match the mating component.
Type 3 – Clevis end	U-shaped end fitting for connection with a pin. It allows a defined pivoting movement around one axis and is suitable for lug-shaped mounting points.
Type 4 – Eye end	Compact end fitting with a through-hole for mounting on a pin. Sufficient radial clearance is required to avoid lateral loads.
Type 5 – Spherical bearing end	Articulated end fitting with a spherical bearing around the mounting hole. It can compensate for angular misalignment and is suitable for changing connection angles.
Type 6 – Extension	Rigid intermediate piece used to extend the connection or adapt the installation length. It does not provide any articulated movement.
Type 7 – Axial joint	Movable joint with an additional connection thread. It allows angular compensation between the gas spring and the mounting point.

Ball joints are particularly suitable where the angle between the gas spring and the mounting point changes during the stroke. Clevis ends and eye ends are appropriate for clearly guided pivoting movements.

Meaning of the Specifications in the Product Table

Specification	Meaning
Type	Identifies the design of the end fitting from Type 1 to Type 7.
Gas spring thread M	Thread of the end fitting that is screwed onto the gas spring connection. The thread size and pitch must match.
Length R	Overall length of the end fitting according to the product drawing. It influences the total installed length of the assembled gas spring.
Material thickness T	Thickness of the end fitting in the connection area, for example on eye ends. This dimension is relevant for the available space between brackets or mounting lugs.
Ball/pin diameter b	Diameter of the corresponding ball or mounting pin. This value must match the mating component.
Hole diameter H	Diameter of the through-hole in eye ends, clevis ends or articulated fittings. It determines the required mounting pin diameter.
Connection thread M2	Thread on the mounting side, for example on a ball stud, axial joint or extension.
Material	Material or surface finish, such as zinc-plated steel, stainless steel, plastic, aluminium or zinc die casting.
Total stock	Total quantity of the article currently held in stock.
Available immediately	Quantity currently available for immediate dispatch.

Not every dimension is required for every type of end fitting. Empty fields or zero values therefore do not necessarily apply to all designs.

How to Select the Right Gas Spring End Fitting

Proceed in the following order:

Check the gas spring thread: Determine the connection thread on the piston rod and cylinder. The gas spring thread M of the end fitting must match.
Define the required movement: Check whether the connection can remain rigid or must compensate for angular movement during the stroke.
Identify the mating component: Compare the ball, pin or hole diameter with the existing mounting point.
Check the installation length: End fittings change the overall distance between the mounting points. Consider the length R at both ends.
Check the available space: Material thickness, ball size and joint movement must not interfere with brackets or adjacent components.
Select the material: Consider humidity, corrosion, temperature and cleaning agents.
Assess the load: The end fitting must be suitable for the force of the gas spring and the actual mounting arrangement.

When replacing an existing fitting, do not compare only the thread and basic shape. The overall length, pin or ball diameter and required freedom of movement must also match.

Installation and Load Transfer

Gas springs should preferably be loaded only in the axial direction. Lateral forces acting on the piston rod, seal or end fittings may cause wear and reduce service life.

Ball joints and spherical bearing ends can compensate for minor angular misalignment. However, they cannot compensate for incorrectly positioned mounting points. Clevis ends and eye ends require sufficient clearance so that they do not become twisted or jammed during movement.

For reliable installation, we recommend:

screwing the end fittings fully onto the gas spring connection thread,
using suitable balls or pins with smooth, burr-free surfaces,
not exceeding the permissible articulation angle of the joint,
aligning both mounting points without distortion or twisting,
checking freedom of movement throughout the entire stroke.

The end fitting and mounting point must not be used as mechanical end stops. The application requires separate stops and sufficient stroke reserve.

Suitable ball studs, angle brackets, flat brackets and pin brackets can be found in our gas spring mounting brackets.

Materials and Corrosion Protection

Zinc-plated steel end fittings are suitable for many general applications in dry or moderately exposed environments. The zinc coating provides limited corrosion protection, which may be reduced by damage or aggressive media.

Stainless steel end fittings are intended for applications with increased requirements for corrosion resistance and cleanliness. Suitability for seawater, chlorides, acids or cleaning agents must nevertheless be assessed according to the actual environment.

Plastic, aluminium and zinc die-cast versions allow lightweight or compact designs. The permissible load and temperature resistance depend on the individual design.

Frequently Asked Questions About Gas Spring End Fittings

Can every end fitting be installed on every gas spring?

No. The connection thread, thread pitch, spring force and dimensions must be suitable for both the gas spring and the mounting arrangement.

Which end fitting provides the best angular compensation?

Ball joints, spherical bearing ends and axial joints provide angular compensation. The most suitable design depends on the required angle, load and mounting type.

Does an end fitting change the overall length of the gas spring?

Yes. End fittings increase the installation length between the mounting points. The length of the fittings at both ends must be taken into account.

What is the difference between end fittings and mounting brackets?

End fittings are screwed directly onto the gas spring. Mounting brackets are attached to the fixed or moving component and provide the matching connection, such as a ball stud or pin bracket.

Can different end fittings be used at each end?

Yes. For example, a ball joint can be used at one end and an eye end at the other, provided that the threads, dimensions, movement and load capacity are suitable for the application.

Further information on selection, installation and mounting position can be found in our Gas Spring FAQ.