Rod-end accessories are an important part of a hydraulic-cylinder assembly. They provide the mechanical connection between the cylinder rod and the moving component of the mold, while their geometry must also allow the accessory to be correctly installed and tightened.
A historical Vega technical case focused on an MFA accessory and two practical questions raised by a Customer: the material and hardness of the accessory, and the difficulty of tightening it because the available tool was larger than the machined faces on the cylinder rod.
The Vega Team’s response provides useful information about the material used in that specific case and, more importantly, shows why the tooling used to install a rod accessory may need to be adapted to the actual rod geometry.
What is an MFA accessory?
Vega currently lists MFA accessories as floating joints for hydraulic-cylinder rods. They connect to the male thread of the rod and provide a floating connection between the cylinder and the component being moved. The range is available in different metric and UNF/UNEF versions and sizes according to the rod-end configuration.
MFA Floating Joint – Vega Cylinders
The current Vega range includes, for example:
- MFA10X150 / MFA3/8-24 for rod Ø18
- MFA12X175 / MFA1/2-20 for rod Ø22
- MFA14X200 / MFA9/16-18 for rod Ø22
- MFA20X250 / MFA3/4-16 for rod Ø28 and Ø36
- MFA27X300 / MFA1-12 for rod Ø36 and Ø45
- MFA33X350 / MFA1-1/4-12 for rod Ø45 and Ø56.
This makes it important to identify the complete accessory configuration rather than referring simply to an “MFA accessory”.
What material is used for the MFA accessory?
In the historical technical exchange, the Customer specifically asked about the steel type and hardness used for the MFA accessory.
The Vega Team replied with the following specifications:
- Material: 42CrMo4
- Hardness: approximately 30–32 HRC.
These values should be understood as the specifications given by Vega for the accessory discussed in that historical case.
They should not automatically be interpreted as a specification for every current MFA configuration unless the corresponding technical documentation confirms it.
Why the material specification matters
The rod accessory is part of the mechanical load path between the hydraulic cylinder and the mold component.
The accessory therefore needs appropriate mechanical properties for the loads generated during operation.
In the documented case, Vega specified 42CrMo4 steel with approximately 30–32 HRC hardness.
The hardness figure is particularly useful because it describes the condition of the component after its manufacturing or heat-treatment process, rather than simply identifying the base steel grade.
The Customer’s tooling problem
The second question concerned installation rather than material.
The Customer explained that there were difficulties tightening the accessory onto the rod because the available tool was larger than the machined faces of the rod. A PDF showing the problem was also attached to the original request.
This is a practical problem that can occur when a standard tool does not match the available wrenching surface on the cylinder rod.
The tool may be suitable for the accessory itself but still be unsuitable for the specific rod geometry.
Why the standard tool did not fit
The Vega Team explained that the thickness of the standard tool was greater than the face of the rod.
In other words, the problem was not necessarily the accessory or the thread.
The limiting factor was the available space around the rod’s wrenching surfaces.
This distinction is important because attempting to solve the problem by simply applying more force to an unsuitable tool can damage the component or make it impossible to achieve a controlled tightening operation.
Vega’s solution: modify the standard tool
The technical response explains that Vega modified the standard tool by reducing its thickness according to the rod.
The approach was therefore:
standard tool → reduce tool thickness → adapt it to the rod geometry
This is a simple but effective example of application-specific tooling.
The important point is that the tool was not necessarily replaced by a completely different commercial product. Instead, the existing standard tool was modified to match the available space around the rod.
Are special tools commercially available?
The Customer also asked whether a special tool could be found at tool shops.
The Vega Team gave a deliberately cautious answer:
It was possible that special tools existed, but Vega had never asked tool shops about them.
Therefore, based on this historical documentation, it would not be correct to state that a particular commercial special tool was available.
What is documented is that Vega had solved the specific problem by modifying the standard tool to reduce its thickness according to the rod.
Rod geometry is part of the installation design
This case highlights an aspect that is sometimes overlooked when specifying hydraulic cylinders.
The cylinder, rod, accessory and installation tool must be considered together.
The actual assembly is:
hydraulic cylinder → rod → MFA accessory → mold component
and each interface has to work correctly.
Vega’s current accessory range is specifically organized according to rod-end thread and rod diameter, confirming the importance of matching the accessory to the cylinder configuration.
Hydraulic Cylinder Accessories – Vega Cylinders
Why a floating joint can be useful
The current Vega documentation describes the MFA as a floating joint.
Its purpose is to provide a connection between the male rod thread and the moving component while allowing the appropriate floating connection.
This is particularly relevant in mold applications where the cylinder rod and the moving component must be connected without unnecessarily introducing unwanted mechanical constraints.
The correct accessory therefore contributes not only to assembly but also to the mechanical behaviour of the complete system.
The accessory must match the rod
The current Vega range demonstrates that MFA accessories are available in several configurations.
For example, an MFA accessory for a Ø18 rod is not simply interchangeable with an MFA configuration intended for a Ø45 rod.
The correct selection depends on parameters such as:
- rod diameter;
- rod-end thread;
- accessory type;
- metric or UNF/UNEF thread;
- required connection geometry.
The official Vega product range lists these combinations explicitly.
Installation tooling should be checked before assembly
A useful lesson from the case is that the tooling should be considered before the cylinder is installed in the mold.
The following should be checked:
- What is the cylinder rod diameter?
- What is the rod-end thread?
- Which MFA configuration is required?
- What are the dimensions of the rod’s wrenching faces?
- How much space is available around the rod?
- Does the standard installation tool fit?
- Can the required tightening operation be performed safely?
If the tool is too thick, the problem should be solved before attempting to tighten the accessory.
Do not assume that a standard tool will always fit
The documented case is particularly useful because the standard tool was not suitable for the rod geometry as supplied.
Vega therefore reduced the thickness of the tool to match the rod.
This demonstrates that “standard accessory” does not necessarily mean “standard installation conditions”.
Even when the accessory itself is a standard product, the available installation space may require a specific tooling solution.
A practical installation checklist
Before installing an MFA accessory, it is useful to verify the following.
1. Identify the cylinder
Record the complete cylinder model and configuration.
2. Identify the rod diameter
The MFA range is divided according to rod diameter.
3. Identify the thread
Confirm the exact rod-end thread, including whether the configuration is metric, UNF or UNEF.
4. Select the correct MFA accessory
Use the corresponding Vega configuration rather than selecting only by appearance.
5. Check the wrenching faces
Measure or verify the available faces on the rod.
6. Check the installation tool
Make sure the tool can physically enter the available space and engage the rod correctly.
7. Adapt the tool if necessary
The historical Vega case demonstrates that reducing the thickness of a standard tool can solve the interference problem.
8. Verify the final assembly
After installation, confirm that the accessory is correctly seated and that the mechanical connection is suitable for the application.
The importance of application-specific solutions
Vega currently also offers custom hydraulic-cylinder solutions, demonstrating that the company can adapt cylinder configurations to specific customer requirements.
Custom Hydraulic Cylinders – Vega Cylinders
The same engineering philosophy can be applied to accessories and installation tooling: the objective is not simply to use a generic component, but to ensure that the complete assembly works correctly under the actual conditions of the application.
A small tooling issue can become a significant maintenance problem
The original Customer was not reporting a failure of the hydraulic cylinder.
The issue was much more practical: the available tool was too large for the rod faces.
Without an appropriate tool, even a correctly selected accessory can become difficult to install.
This is why installation requirements should be considered during the design and purchasing stages, rather than only when the cylinder arrives at the mold shop.
Conclusion
The MFA accessory case demonstrates that correct hydraulic-cylinder installation involves more than selecting the correct thread.
In the historical Vega technical exchange, the Customer asked about the material and hardness of the MFA accessory and reported difficulty tightening it because the available tool was larger than the rod’s wrenching faces.
The Vega Team specified 42CrMo4 steel and approximately 30–32 HRC hardness for the accessory discussed in that case.
For the tooling problem, Vega explained that the standard tool was thicker than the available rod face and had therefore been modified by reducing its thickness according to the rod geometry.
Regarding the possibility of purchasing a special tool from a tool shop, the historical documentation does not confirm availability. Vega only stated that special tools might exist but that the company had never checked with tool shops.
The main lesson is:
A hydraulic-cylinder accessory is only part of the solution. The rod geometry, accessory configuration and installation tooling must also be considered to achieve a correct and practical assembly.
Useful and Verified URLs
- MFA Floating Joints – Vega Cylinders — Official Vega page for the current MFA floating-joint range, including available thread and rod-diameter configurations.
- Hydraulic Cylinder Accessories – Vega Cylinders — Official Vega accessories section covering rod accessories, including MFA, MTA and other components.
- VR Hydraulic Cylinder Accessories – Vega Cylinders — Official Vega page covering rod accessories and other accessories used for hydraulic-cylinder installation and setup.
- Custom Hydraulic Cylinders – Vega Cylinders — Official Vega page describing custom hydraulic-cylinder solutions for application-specific requirements.
- Hydraulic Cylinder Catalog – Vega Cylinders — Official Vega catalog page with the current hydraulic-cylinder families and application categories.
