How to Choose the Right Leather Packing for Your Application
Choosing the right leather packing is about more than finding a component that fits. The dimensions and profile of a seal or packing are important, but they are only part of the equation. Pressure, temperature, movement, the material being sealed, equipment condition, clearances, and the intended service all influence whether a sealing component will perform as expected.
For engineers, maintenance professionals, equipment manufacturers, and organizations maintaining legacy machinery, understanding the application is the first step toward selecting the right leather packing. At Monarch-McLaren, we manufacture leather seals and mechanical leather packings for a wide range of hydraulic, pneumatic, water-well, industrial, and specialty applications. Our approach starts with understanding what the component needs to do—not simply what it needs to look like.
What Is Leather Packing Used For?
Leather packing is used as a mechanical sealing material in applications where a component must help control the movement of a fluid or prevent the passage of material around moving or stationary components.
Depending on the design, leather packing can be used in applications including:
- Hydraulic equipment
- Pneumatic equipment
- Industrial pumps
- Water-well systems
- Hoists and presses
- Air engines and compressors
- Legacy and vintage machinery
- Specialty equipment
- Restoration applications
Different packing designs are suited to different mechanical arrangements. For example, U packing is designed for reciprocating pistons, plungers, or rams, while Vee packing is commonly used for hydraulic or pneumatic piston-head applications. Cup packing can be used in hoists, presses, air engines, and hand pumps, while well cup packing is designed for deep-well applications.
The important point is that leather packing is not a single product or a one-size-fits-all solution. The design and material need to match the application.
How Do You Choose Leather Packing?
A good leather packing selection begins by understanding the operating conditions. Before selecting a leather seal or packing, consider these key factors:
What type of movement is involved?
Is the seal stationary, reciprocating, or exposed to another type of movement?
A packing component designed for a reciprocating piston may have very different requirements from one used around a stationary shaft. Understanding the movement helps determine the appropriate packing profile and design.
What pressure will the packing experience?
Pressure is one of the most important considerations in seal selection. The packing needs to maintain an effective seal under the pressure generated by the equipment without excessive extrusion or deformation.
Mechanical leather packings are known for their resistance to cold flow and their ability to withstand demanding pressure conditions. However, the appropriate design and material still depend on the specific application.
What temperature will the seal encounter?
Temperature can affect the performance and service life of sealing materials. Consider both the normal operating temperature and any temperature extremes the component may encounter. Leather has characteristics that can make it useful across a range of operating environments, including resistance to becoming brittle in sub-zero conditions. The specific application should still be evaluated before selecting a material.
What medium is being sealed?
What is the component actually sealing?
The answer could be water, hydraulic fluid, air, or another medium. The compatibility of the leather and any treatment or impregnation with the application should be considered as part of the selection process. This is particularly important for water-service applications. Monarch-McLaren uses Oak leather for many water-service components, including water-well cups, while other leather types are used for different applications.
What are the equipment dimensions and clearances?
Dimensions remain critical.
Important information can include:
- Inside diameter
- Outside diameter
- Cross-section
- Overall height or stack height
- Groove or housing dimensions
- Shaft or piston dimensions
- Available clearances
For replacement applications, an existing component, drawing, sample, or even detailed measurements can provide valuable information. However, dimensions should be evaluated alongside the operating conditions. A component that physically fits may not necessarily be the correct sealing solution.
What Type of Leather Is Used for Seals?
There is no single type of leather used for every leather seal or packing application. Monarch-McLaren works with several types of leather, including Vegetable Tanned Oak leather, Chrome leather, Military Chrome, and Retan leather.
Vegetable Tanned Oak leather is used for many water-service components, including water-well cups, where moisture resistance is important.
Chrome leather is a tougher-grain leather used in certain applications.
Military Chrome is primarily used where government specifications call for chrome leather.
Retan leather is used for the majority of Monarch-McLaren’s leather packings.
The appropriate material depends on the requirements of the application, including the service conditions and applicable specifications.
Why Is Leather Used for Mechanical Seals and Packing?
Leather remains relevant as an industrial sealing material because it combines several useful characteristics. Mechanical leather packings are pliable yet tough and highly resistant to wear. Leather’s natural fiber structure contributes to its ability to conform to mating surfaces while maintaining strength.
Other characteristics of mechanical leather packing include:
- Low coefficient of friction
- Resistance to cold flow
- High abrasion resistance
- Ability to adapt to back supports
- Ability to accommodate greater wear clearances in appropriate applications
- Adaptability through different impregnations
- Resistance to becoming brittle in sub-zero temperatures
- Natural lubricity from the surface characteristics of leather
Its low coefficient of friction can help reduce heat generation, while its wear characteristics can contribute to longer service life in suitable applications. These characteristics help explain why leather packing continues to be specified for certain modern industrial applications as well as older equipment.
When Should Leather Packing Be Impregnated?
Leather packings can be impregnated with different materials to make them adaptable to different types of service. The purpose is not simply to add another material to the component. The treatment should be considered in relation to the operating environment and performance requirements.
The appropriate impregnation can depend on factors such as the medium being sealed, operating conditions, and the desired characteristics of the finished packing. For that reason, impregnation should be considered as part of the overall material-selection process rather than as an afterthought.
What Are the Different Types of Leather Packing?
Leather packing comes in several designs, each intended for particular applications.
Flange Packing – Flange packing is designed to help prevent the passage of foreign material along shafts or piston rods.
Vee Packing – Vee packing is well suited to hydraulic or pneumatic piston-head applications. Its multi-ring configuration allows the packing to work with the equipment’s sealing arrangement.
U Packing – U packing is designed to seal reciprocating pistons, plungers, or rams.
Cup Packing – Cup packing is used in applications including hoists, presses, air engines, and hand pumps.
Well Cup Packing – Well cup packing is designed for deep-well applications and water-well pumping systems.
Custom Packing – When a standard packing profile or dimension does not meet the requirements of an application, custom packing can be manufactured to specific requirements. The correct choice depends on the equipment design and operating conditions—not simply on the name of the packing style.
How Do I Select a Replacement Leather Seal?
Replacing an existing leather seal can be straightforward when the original part number and specifications are available. It can be more challenging when the equipment is older, the original manufacturer is no longer operating, or replacement parts are no longer readily available. In those situations, gather as much information as possible.
Useful information may include:
- Original part number
- Dimensions
- Equipment manufacturer and model
- Drawings
- Photographs
- Existing seal or packing sample
- Operating pressure
- Operating temperature
- Type of movement
- Medium being sealed
- Quantity required
- Any applicable military or industry specifications
An old or damaged component can still provide valuable information. For obsolete or difficult-to-source components, custom manufacturing may provide an alternative to replacing an otherwise functional piece of equipment.
Are Leather Seals Suitable for Hydraulic Applications?
Leather seals and packings can be suitable for certain hydraulic applications, depending on the equipment and operating conditions. Leather has long been used in hydraulic sealing because of characteristics including flexibility, wear resistance, low friction, and resistance to cold flow. However, no sealing material should be selected solely because it has worked in another hydraulic application.
Pressure, temperature, fluid compatibility, movement, clearances, surface condition, and packing design all need to be considered. In other words, the question isn’t simply whether leather can be used in hydraulics. The question is whether the specific leather packing is appropriate for the specific hydraulic application.
Are Leather Seals Suitable for Water-Well Applications?
Yes. Leather packing has a long history of use in water-well applications. Water-well cups are one example of a specialized leather sealing component. Monarch-McLaren uses Oak leather for many water-service parts because of its moisture-resistant characteristics. The correct well cup design and dimensions still depend on the pump and application. For replacement water-well components, information about the existing equipment and dimensions can help determine the appropriate component.
When Should You Consider Custom Leather Packing?
Custom leather packing can make sense when a standard component does not meet the requirements of the equipment.
Examples include:
- Obsolete replacement parts
- Unusual dimensions
- Non-standard profiles
- Legacy machinery
- Restoration projects
- Equipment without readily available OEM replacement parts
- Components requiring specific materials or treatments
- Applications requiring a particular specification
Custom manufacturing does not necessarily mean creating an entirely new product. In many cases, it means reproducing or adapting a proven sealing component to match the requirements of a particular machine. This can be particularly valuable when the equipment itself is still reliable but the original replacement parts are no longer available.
What Information Should You Provide When Ordering Leather Packing?
The more application information available, the easier it is to evaluate the appropriate sealing solution. When requesting a quote or discussing a replacement component, consider providing:
Part information
- Part number
- Drawing
- Existing sample
- Photographs
Dimensions
- Inside diameter
- Outside diameter
- Cross-section
- Height or stack dimensions
Operating conditions
- Pressure
- Temperature
- Speed
- Type of movement
- Sealing medium
Equipment information
- Manufacturer
- Model
- Equipment type
- Application
If some of this information is unavailable, don’t assume that means the component cannot be reproduced. For older or custom equipment, the available information may be enough to begin evaluating the application.
The Right Leather Packing Starts With the Application
Selecting leather packing is not simply a matter of matching a part number or finding a component with the right dimensions. The best sealing solution considers the complete application: what is being sealed, how the equipment moves, what pressure and temperature it experiences, what material it contacts, and what conditions the component must withstand.
Leather remains a valuable sealing material because its natural characteristics can provide a useful combination of flexibility, toughness, wear resistance, low friction, and adaptability. But material selection is only part of the equation. The right packing profile, leather type, dimensions, treatment, and manufacturing approach all need to work together. At Monarch-McLaren, we combine decades of experience working with leather sealing materials with custom manufacturing capabilities to help customers address both standard and unusual sealing requirements.
Have a replacement seal, packing, or obsolete component that is difficult to identify?
Start with the information you have. Our team can help evaluate the application and determine the appropriate path forward. Our team specializes in manufacturing both standard and custom leather sealing solutions engineered to match your application’s unique requirements.
Contact us today to discuss your application, request a quote, or learn how we can help keep your equipment operating for years to come.
