Anti-Vibration Parts

What are anti-vibration parts?

Anti-vibration parts are rubber and rubber-to-metal components used to isolate vibration, absorb shock, and reduce noise between a machine and its mounting surface. Engines, motors, pumps, compressors, fans, generators, and many other machines create vibration while they run. Without isolation, that vibration passes straight into the frame, floor, or structure, causing noise, wear, loosening of fasteners, cracking, and discomfort. Anti-vibration mounts sit between the machine and its base, flexing to absorb vibration and shock so it does not travel through the rest of the system.

The most common anti-vibration part is the bobbin mount, a cylinder of rubber bonded between two metal end plates, each with a threaded stud or threaded hole. Bobbin mounts are compact, simple to fit, and available in a wide range of sizes, threads, and rubber hardnesses.

Bobbin mounts are usually described by:

• Diameter - the outside diameter of the rubber body, such as 15 mm or 25 mm
• Height - the height of the rubber body between the metal plates, such as 10 mm or 15 mm
• Thread size - the size of the threaded studs or holes, such as M4, M5, M6, or M8
• Thread length - the length of the threaded studs
• End configuration - male/male, male/female, female/female, or single-ended
• Rubber type and hardness - such as natural rubber in a given Shore A hardness

For example, a 15 × 15 mm male/male anti-vibration bobbin with M5 studs has a 15 mm diameter, a 15 mm rubber height, and an M5 threaded stud on each end.

Key features:

• Vibration isolation - reduces vibration passing from machines into frames, floors, and structures
• Shock absorption - cushions sudden impacts and loads
• Noise reduction - helps reduce structure-borne noise and rattles
• Protects equipment - reduces wear, fatigue, and loosening of parts
• Simple fitting - threaded studs and holes allow quick, easy installation
• Range of sizes and threads - to suit small fans and electronics through to engines and heavy machinery
• Choice of rubber - natural rubber, neoprene, and nitrile to suit different environments

In simple terms, anti-vibration parts are flexible mounts that stop vibration and shock travelling from a machine into everything around it.

Why are anti-vibration parts essential?

Anti-vibration parts are essential because uncontrolled vibration causes a wide range of problems. It can make machines noisy, loosen bolts, crack brackets and welds, wear out bearings, damage sensitive electronics, and make workplaces and vehicles uncomfortable. Vibration can also travel through floors and walls, affecting nearby equipment and people. Fitting the right anti-vibration mounts reduces these problems, protecting both the machine and its surroundings.

Their main benefits are:

• Longer equipment life - reduces wear and fatigue on machines, frames, and components
• Quieter operation - reduces noise and rattles transmitted into structures
• Protects sensitive equipment - shields electronics, instruments, and controls from vibration and shock
• Fewer loose fasteners - less vibration means bolts and fixings stay tight for longer
• Reduced cracking and damage - lowers stress on welds, brackets, and housings
• Improved comfort - reduces vibration felt by operators and passengers
• Easier installation - mounts can compensate for small misalignments and uneven surfaces
• Cost-effective - inexpensive parts that prevent costly damage and downtime

Anti-vibration parts are used across a wide range of industries and applications, including:

• Engines and generators - mounting engines, gensets, and power units
• Motors and pumps - isolating electric motors, pumps, and drives
• Fans and HVAC - mounting fans, blowers, air handling units, and air conditioning equipment
• Compressors - isolating air compressors and refrigeration units
• Electronics and control panels - protecting circuit boards, instruments, and enclosures
• Automotive and transport - exhausts, radiators, cabs, and auxiliary equipment
• Agricultural and construction machinery - cabs, engines, and equipment mountings
• Industrial machinery - machine tools, conveyors, vibrating screens, and production equipment
• Marine - engines, pumps, and onboard equipment
• Hobby and DIY - 3D printers, CNC machines, fans, and small machinery

The main types of anti-vibration parts

Anti-vibration parts are usually grouped by their design, end configuration, rubber type, and the loads they carry.

Bobbin mounts by end configuration:

• Male/male bobbins - a threaded stud on both ends, bolted through holes in the machine and base with nuts
• Male/female bobbins - a threaded stud on one end and a threaded hole on the other, useful where one side has a tapped hole
• Female/female bobbins - threaded holes on both ends, fixed with bolts or setscrews from each side
• Single-ended buffers - a stud or threaded hole on one end and a plain rubber face on the other, used as bump stops and buffers to absorb impacts

Other anti-vibration mounts:

• Cup mounts - a rubber element enclosed in a metal cup, often with a fail-safe design that holds the machine if the rubber fails, used for engines and generators
• Conical mounts - cone-shaped mounts that handle loads in several directions, used for engines and heavy equipment
• Machine feet and levelling mounts - adjustable feet with rubber pads that isolate vibration and level machines on the floor
• Rubber buffers and bump stops - absorb impacts and limit travel
• Anti-vibration pads and sheets - rubber pads placed under machines to reduce vibration and noise
• Rubber bushes - fitted into eyes and brackets to isolate vibration at pivots and mounting points
• Exhaust and radiator mounts - flexible mounts for vehicle and machinery exhausts and cooling systems

By rubber type:

• Natural rubber - offers excellent vibration isolation and flexibility, ideal for most general-purpose applications. It is not suitable for prolonged contact with oils and fuels
• Neoprene - offers good resistance to weather, ozone, and moderate oil exposure, ideal for outdoor applications
• Nitrile rubber - offers good resistance to oils, fuels, and greases, ideal for engines and machinery where oil contact is likely
• Silicone rubber - handles high and low temperatures, used in demanding environments

By rubber hardness:

• Soft rubber - lower Shore hardness gives better vibration isolation, but carries lower loads
• Medium rubber - a balance of load capacity and isolation for general use
• Hard rubber - higher Shore hardness carries heavier loads and resists movement, but isolates vibration less effectively

By material of metal parts:

• Zinc plated steel - the standard choice, with good corrosion protection
• Stainless steel - for wet, marine, food, and corrosive environments

How to choose the right anti-vibration parts?

Choosing the right anti-vibration parts means matching them to the weight of the machine, the type of vibration, and the way the mounts will be loaded. Work through these points in order:

• Machine weight - work out the total weight of the machine and divide it by the number of mounts to find the load on each mount. Allow for uneven weight distribution, as some mounts may carry more than others
• Load direction - bobbin mounts carry much higher loads in compression, where they are squeezed, than in shear, where the load acts sideways. Avoid loading mounts in tension, where they are pulled apart
• Load capacity - choose a mount with a rated load that suits the load on each mount, in the direction it will be loaded
• Vibration frequency - consider the running speed of the machine. For good isolation, the mount needs to be soft enough that its natural frequency is well below the machine’s vibration frequency
• Rubber hardness - choose softer rubber for better isolation of lighter loads, and harder rubber for heavier loads or where less movement is wanted
• Size and height - choose a diameter and height that fit the available space, remembering that taller mounts generally give more deflection and better isolation
• Thread size and configuration - choose male/male, male/female, or female/female ends to suit the mounting holes, and check the thread size and length
• Shock loads - choose buffers or cup mounts where impacts or sudden loads are expected
• Environment - choose natural rubber for general use, neoprene for outdoor and weather exposure, and nitrile for oil and fuel resistance
• Temperature - check that the rubber suits the operating temperature, especially near engines and hot equipment
• Movement limits - consider whether the machine needs to be restrained from excessive movement, and use fail-safe mounts or buffers where needed
• Quality and brand - choose mounts from reputable suppliers for consistent rubber quality, strong bonding, and reliable load ratings

How to fit anti-vibration mounts

Fitting mounts correctly helps them work effectively and last longer:

• Choose enough mounts - use enough mounts to support the machine evenly, usually one at each corner or mounting point
• Position them correctly - place mounts so they share the load evenly and are loaded mainly in compression
• Use washers - use washers under nuts to spread the load and protect the metal plates
• Tighten carefully - tighten nuts and bolts firmly but do not overtighten, as this can damage the threads or the rubber bond
• Hold the metal parts - when tightening, hold the metal plate or stud rather than twisting the rubber body
• Avoid twisting and stretching - do not load the mounts in tension or twist the rubber during installation
• Keep away from oil - protect natural rubber mounts from oil, fuel, and solvents, or use nitrile mounts where contact is likely
• Check after running - check the mounts and fixings after the machine has run for a while, and retighten if needed

FAQ - All you need to know about anti-vibration parts

What is an anti-vibration bobbin?

An anti-vibration bobbin is a cylinder of rubber bonded between two metal plates, each with a threaded stud or threaded hole. It is fitted between a machine and its base to absorb vibration and shock.

What does male/male mean on an anti-vibration mount?

Male/male means the mount has a threaded stud on both ends. Male/female has a stud on one end and a threaded hole on the other, and female/female has threaded holes on both ends.

What do the sizes on an anti-vibration bobbin mean?

Sizes are usually given as diameter × height, followed by the thread size. For example, a 15 × 15 mm M5 bobbin has a 15 mm diameter, a 15 mm rubber height, and M5 threads.

How do I know what load my mounts need to carry?

Divide the total weight of the machine by the number of mounts, and allow for uneven weight distribution. Then choose mounts rated for at least that load in the direction they will be loaded.

Should mounts be loaded in compression or shear?

Bobbin mounts carry the most load in compression. They can also work in shear, which gives softer isolation but lower load capacity. Avoid loading them in tension, as this can pull the rubber away from the metal.

What rubber hardness should I choose?

Softer rubber gives better vibration isolation for lighter loads, while harder rubber carries heavier loads with less movement. Choose a hardness that balances the load and the level of isolation you need.

What is the difference between natural rubber, neoprene, and nitrile mounts?

Natural rubber gives the best vibration isolation for general use. Neoprene resists weather and ozone, making it better outdoors. Nitrile resists oil and fuel, making it ideal for engines and machinery.

Why are my anti-vibration mounts not reducing vibration?

Common causes include mounts that are too hard or overloaded, mounts loaded in the wrong direction, too few mounts, or rigid connections such as pipes and cables bypassing the mounts. Check the load, rubber hardness, and installation.

Why did my anti-vibration mount fail?

Common causes include overloading, loading in tension, overtightening, twisting the rubber during fitting, exposure to oil or fuel, high temperatures, and ageing. Choose the correct mount and fit it carefully.

How long do anti-vibration mounts last?

It depends on load, temperature, environment, and vibration levels. Inspect mounts regularly and replace them if the rubber is cracked, perished, swollen, separating from the metal, or permanently squashed.

Can I use anti-vibration mounts outdoors?

Yes. Neoprene mounts with zinc plated or stainless steel metal parts are well suited to outdoor use, as they resist weather, ozone, and corrosion.