Pillow Block Bearings: Types, Sizes & Complete Buying Guide
- sociocon20
- Aug 16
- 12 min read
If you're looking for pillow block bearings, choosing the right one isn't simply about matching the shaft diameter. The bearing housing, bearing type, load, operating speed, shaft arrangement, mounting position, lubrication, and operating environment all need to be considered before making a purchase.
At Kashyap Bearing, we help customers identify suitable pillow block bearings based on the actual machine requirement rather than selecting a unit only by size. Whether you need pillow block bearings for conveyors, agricultural machinery, industrial equipment, fans, pumps, material-handling systems, or general machinery, you can share the bearing number, shaft size, dimensions, photograph, or application details with our team.
Kashyap Bearing has been serving customers from SP Road, Bangalore since 1987, supplying a wide range of bearings and industrial products for different applications.
What Is a Pillow Block Bearing?
A pillow block bearing is a bearing mounted inside a housing that provides support for a rotating shaft.
Instead of installing a bearing separately into a machine housing, a pillow block unit combines:
Bearing
Housing
Mounting arrangement
into a single assembly.
This makes pillow block bearings particularly convenient for applications where a shaft needs to be supported externally along its length.
They are commonly used in:
Conveyor systems
Agricultural machinery
Industrial machinery
Material-handling equipment
Fans and blowers
Packaging machinery
Textile machinery
Food-processing equipment
Manufacturing equipment
The bearing inside the housing can vary depending on the design and application.
Why Are Pillow Block Bearings Used?
The main advantage of a pillow block bearing is its simple and convenient mounting arrangement.
Instead of designing a separate housing for a standard bearing, a pillow block unit can be mounted directly onto the machine structure.
This can make installation and replacement easier.
Pillow block units can provide:
Shaft support
Easy installation
Convenient bearing replacement
Stable mounting
Protection for the bearing
Flexible mounting options
Suitable support for long shafts
They are especially useful when a shaft needs to be supported at multiple points along its length.
How Does a Pillow Block Bearing Work?
A pillow block bearing consists of a bearing mounted inside a housing.
The housing is fixed to the machine frame, while the shaft rotates through the bearing.
The bearing allows the shaft to rotate while reducing friction between the shaft and the stationary housing.
Depending on the bearing construction, the internal bearing may use:
Balls
Rollers
Spherical rolling elements
The housing itself provides the external support and mounting structure.
The exact performance depends on the bearing design, housing material, sealing arrangement and operating conditions.
Main Types of Pillow Block Bearings
Pillow block bearings are available in several configurations.
Understanding the different types can help you select the appropriate unit for your machine.
Standard Pillow Block Bearings
Standard pillow block bearings are among the most commonly used bearing units.
They generally consist of a bearing mounted inside a housing with a base designed for installation on a flat surface.
They are commonly used in:
Conveyors
Fans
Industrial machinery
Agricultural equipment
Material-handling systems
They are a practical choice for general shaft-support applications.
Self-Aligning Pillow Block Bearings
Self-aligning pillow block bearings are designed to accommodate a certain amount of shaft misalignment.
This can be useful when:
Shaft alignment isn't perfect
Housing mounting surfaces aren't completely aligned
Shaft deflection occurs
Multiple bearing supports are used
The self-aligning feature helps reduce the effects of small alignment errors.
However, self-alignment has limits and should not be treated as a solution for major installation misalignment.
Flanged Bearing Units
Flanged bearing units are mounted using a flange rather than the traditional base arrangement.
They can be useful where the bearing needs to be mounted against a vertical or side surface.
Common configurations include:
Two-bolt flanges
Three-bolt flanges
Four-bolt flanges
The correct configuration depends on the machine's mounting arrangement.
Take-Up Bearing Units
Take-up bearing units are designed for applications where shaft position needs to be adjusted.
They are commonly used in:
Conveyor systems
Belt-driven machinery
Material-handling equipment
The housing can move along a mounting frame to help adjust shaft position and belt tension.
Cartridge Bearing Units
Cartridge-style bearing housings can be installed into a prepared mounting arrangement.
They are useful where a compact or specialized mounting configuration is required.
The exact design depends on the bearing manufacturer and application.
Split Pillow Block Units
Split bearing housings can be separated into sections to simplify bearing installation and maintenance.
They can be particularly useful for:
Large shafts
Heavy machinery
Industrial equipment
Applications where shaft removal is difficult
Split housing designs can make bearing replacement easier without completely dismantling the shaft assembly.
Pillow Block Bearing vs Standard Bearing
A common question is the difference between a pillow block bearing and a standard bearing.
A standard bearing generally refers to the bearing itself.
A pillow block bearing is usually a complete bearing unit consisting of a bearing and housing.
Feature | Pillow Block Bearing | Standard Bearing |
Housing included | Yes | Usually no |
Installation | Relatively simple | Requires separate housing or mounting arrangement |
Shaft support | External housing | Depends on machine design |
Replacement | Unit can often be replaced as an assembly | Bearing replaced separately |
Common use | Conveyors, machinery, shafts | Motors, gearboxes, general rotating equipment |
Mounting flexibility | High | Depends on housing |
For a simple shaft-support application, a pillow block unit can be much more convenient.
Pillow Block Bearing vs Plummer Block
Pillow block bearings and plummer blocks are sometimes used interchangeably, but their designs can differ.
A typical pillow block unit is often a compact housing with a bearing mounted inside.
A plummer block generally refers to a larger housing arrangement, often used for heavier-duty applications.
Plummer blocks can be designed to accommodate:
Larger shafts
Higher loads
Heavy industrial machinery
Split bearing arrangements
The terminology can also vary between manufacturers and regions, so it is always better to check the exact bearing unit specification.
Pillow Block Bearing Sizes
Pillow block bearings are available in different sizes to accommodate different shaft diameters and load requirements.
When selecting a pillow block bearing, check:
Shaft diameter
Housing dimensions
Overall height
Mounting hole spacing
Mounting hole size
Bearing width
Overall unit length
The shaft diameter is one of the most important dimensions, but it isn't the only one.
Two pillow block units designed for the same shaft diameter may have different housing dimensions and mounting arrangements.
Common Pillow Block Bearing Sizes
Pillow block bearing units are available for a wide range of shaft sizes.
Depending on the manufacturer and bearing series, common shaft sizes can include:
12 mm
15 mm
17 mm
20 mm
25 mm
30 mm
35 mm
40 mm
50 mm
60 mm
Larger industrial shaft sizes
The exact dimensions and bearing designation should always be verified before ordering.
If you're replacing an existing unit, matching only the shaft diameter may not be enough.
The mounting dimensions also need to match the machine.
How to Read a Pillow Block Bearing Number
Pillow block bearing designations can look confusing at first.
The bearing number generally identifies information about the bearing insert or unit, while suffixes can indicate details such as:
Housing arrangement
Sealing
Locking method
Bore size
Special construction
Different manufacturers may use different naming conventions.
Therefore, don't assume that two bearing numbers with similar-looking codes are interchangeable.
If you have an existing bearing, providing the complete number and a photograph can make identification much easier.
How to Choose the Right Pillow Block Bearing
Choosing the right pillow block bearing involves looking at both the bearing and the housing.
Check the Shaft Diameter
Start by measuring the shaft diameter.
The bearing bore needs to match the shaft correctly.
Common shaft measurements can include:
20 mm
25 mm
30 mm
40 mm
50 mm
Don't round off the measurement.
A small difference can affect mounting and bearing performance.
Check the Load
Determine the load acting on the bearing.
Consider:
Radial load
Axial load
Shock load
Continuous load
Intermittent load
For heavy machinery, load calculation becomes particularly important.
Check Operating Speed
Find out the shaft's operating RPM.
High-speed applications may require a bearing unit designed specifically for higher rotational speeds.
Factors such as lubrication, sealing and bearing type can affect permissible speed.
Check the Shaft Alignment
Determine whether the shaft is likely to experience misalignment.
If there is a possibility of shaft deflection or minor mounting misalignment, a self-aligning bearing unit may be appropriate.
However, serious alignment problems should be corrected rather than relying entirely on the bearing's self-aligning capability.
Check Mounting Space
Measure the available installation area.
Check:
Base width
Mounting hole spacing
Overall height
Unit length
Clearance around the housing
This prevents ordering a bearing that fits the shaft but cannot be installed correctly.
Check the Operating Environment
Consider whether the pillow block will be exposed to:
Dust
Water
Mud
Chemicals
Coolant
High temperatures
Outdoor conditions
The appropriate seal and housing construction can depend on the environment.
Check Lubrication
Some pillow block bearing units are supplied with grease and can be relubricated through a grease fitting.
Check:
Lubrication interval
Grease type
Operating temperature
Operating speed
Over-lubrication can also create problems, especially in high-speed applications.
What to Actually Check Before You Buy
Before purchasing a pillow block bearing, don't simply tell the supplier the shaft diameter.
Provide as much information as possible.
Check the Existing Bearing Number
If you're replacing an existing unit, look for the complete bearing or housing number.
Take a clear photograph if the marking is difficult to read.
Measure the Shaft
Measure the shaft diameter accurately.
If the shaft is worn, check the measurement at multiple points.
Check the Mounting Dimensions
Measure:
Mounting hole distance
Hole diameter
Base dimensions
Overall height
Unit length
This helps ensure the replacement will fit the machine.
Check Radial and Axial Loads
Provide the approximate loads acting on the bearing.
This is especially important for:
Conveyors
Belt drives
Gear drives
Agricultural machinery
Heavy industrial equipment
Check RPM
Tell the supplier the normal operating speed and whether the machine operates continuously.
Check Alignment
Determine whether the shaft is rigidly aligned or whether minor misalignment is expected.
Check the Environment
Tell the supplier if the bearing operates around water, dust, chemicals, mud, coolant or high temperatures.
Check the Locking Arrangement
Pillow block bearings can use different shaft-locking methods.
Depending on the bearing type, this can include:
Set screws
Eccentric locking rings
Adapter sleeves
Other locking arrangements
The locking method needs to be compatible with the shaft and application.
Common Pillow Block Bearing Locking Methods
The bearing insert needs to be securely fixed to the rotating shaft.
Different pillow block designs use different methods.
Set Screw Locking
Set screw bearings use screws that tighten against the shaft.
They are simple and commonly used in general industrial applications.
Eccentric Locking
An eccentric locking ring uses an offset locking arrangement to secure the bearing to the shaft.
It can provide a secure connection for suitable applications.
Adapter Sleeve Locking
Adapter sleeves are used with certain bearing arrangements and can be particularly useful for larger bearings or specific mounting requirements.
The correct method depends on the bearing design.
Common Applications of Pillow Block Bearings
Conveyor Systems
Pillow block bearings are widely used in conveyor systems to support rotating shafts.
They can be found in:
Belt conveyors
Roller conveyors
Material-handling systems
Packaging conveyors
Industrial conveyor lines
The bearing needs to handle the radial load generated by the conveyor and its transported material.
Agricultural Machinery
Agricultural equipment operates in demanding environments involving:
Dust
Dirt
Moisture
Vibration
Shock
Pillow block bearings are commonly used to support shafts in various agricultural machines.
Proper sealing and maintenance are particularly important in these environments.
Fans and Blowers
Fans and blowers require reliable shaft support during continuous rotation.
A properly selected pillow block unit can provide external support for fan shafts.
Textile Machinery
Textile machinery often contains multiple rotating shafts that operate continuously.
Pillow block bearings can be used in suitable shaft-support applications.
Packaging Machinery
Packaging equipment requires reliable movement and rotation for:
Rollers
Conveyors
Drive shafts
Material-handling systems
Pillow block units can provide convenient shaft support.
Industrial Machinery
Pillow block bearings are used in numerous industrial machines where a rotating shaft needs external support.
Applications can include:
Processing machinery
Material-handling equipment
Manufacturing systems
Production equipment
Mechanical drives
Advantages of Pillow Block Bearings
Easy Installation
The integrated housing makes installation relatively straightforward.
Convenient Replacement
The complete unit can often be replaced without designing a separate housing.
Good Shaft Support
They provide stable support for rotating shafts.
Wide Range of Sizes
Pillow block units are available for different shaft diameters and load requirements.
Flexible Applications
They are suitable for conveyors, agricultural machinery, industrial equipment and many other machines.
Easy Lubrication
Many designs include provisions for relubrication.
Limitations of Pillow Block Bearings
Pillow block bearings also have some limitations.
Larger Installation Footprint
The housing takes more space than a bearing installed directly into a compact machine housing.
Alignment Still Matters
Self-aligning designs can accommodate limited misalignment, but incorrect installation can still cause premature failure.
Housing Must Match the Application
The housing material and design need to withstand the machine's operating conditions.
Not Every Unit Handles High Loads
Heavy-duty applications may require specialized bearing and housing arrangements.
Contamination Can Cause Problems
Dust, water and other contaminants can affect bearing life if the sealing arrangement isn't suitable.
Pillow Block Bearing Maintenance
Proper maintenance can help extend bearing life.
Inspect Regularly
Look for:
Unusual noise
Excessive vibration
Temperature increase
Grease leakage
Housing movement
Shaft movement
Lubricate Correctly
Follow the recommended lubrication interval and use a suitable grease.
Avoid adding excessive grease.
Check Mounting Bolts
Loose mounting bolts can allow the housing to move during operation.
Inspect the mounting arrangement periodically.
Check the Shaft
Inspect the shaft for:
Wear
Corrosion
Damage
Improper locking
Excessive movement
Monitor Operating Temperature
An unexpected increase in bearing temperature can indicate:
Over-lubrication
Misalignment
Excessive load
Bearing damage
Incorrect installation
Investigate the cause instead of simply adding more grease.
Common Mistakes When Buying Pillow Block Bearings
Choosing Only by Shaft Diameter
A bearing can fit the shaft but have incompatible mounting dimensions.
Ignoring the Housing
The housing is part of the complete bearing unit and needs to match the application.
Ignoring Load
A small pillow block bearing shouldn't be used simply because it fits the shaft.
Ignoring RPM
Operating speed can affect bearing life, lubrication and temperature.
Choosing the Wrong Locking Method
The shaft-locking mechanism needs to be compatible with the shaft and machine.
Ignoring the Environment
A bearing used outdoors or around water requires different considerations from one used in a clean indoor machine.
Over-Lubricating
Adding too much grease can increase heat generation and may reduce bearing performance.
Why Buy Pillow Block Bearings From Kashyap Bearing?
When sourcing pillow block bearings in Bangalore, the challenge isn't simply finding a unit with the correct bore size.
The important part is matching the bearing insert, housing, shaft diameter, load, speed, mounting arrangement, locking method, lubrication and operating environment to your actual application.
At Kashyap Bearing, you can share your existing bearing number, photograph, shaft dimensions or machine requirements with the team.
This makes it easier to identify the appropriate pillow block unit rather than selecting one based only on shaft diameter.
Kashyap Bearing has been serving customers from SP Road, Bangalore since 1987, supplying a broad range of bearings and industrial products.
Whether you need pillow block bearings for a conveyor, agricultural machine, packaging system, fan, blower, textile machine or industrial equipment, providing the actual application details can help narrow down the right product.
If you're unsure whether you need a standard pillow block, self-aligning unit, flanged bearing, take-up unit or another housing arrangement, speak with the Kashyap Bearing team before purchasing.
The right pillow block bearing isn't necessarily the largest or most expensive option. It is the one that correctly matches the shaft, load, speed and operating environment.
Frequently Asked Questions on pillow block bearing
What is a pillow block bearing?
A pillow block bearing is a bearing mounted inside a housing that supports a rotating shaft. The housing can be directly mounted to the machine structure.
What are pillow block bearings used for?
They are commonly used to support rotating shafts in conveyors, agricultural machinery, fans, blowers, packaging equipment, textile machinery and industrial machines.
What are the main types of pillow block bearings?
Common types include standard pillow blocks, self-aligning units, flanged bearing units, take-up units, cartridge units and split housing arrangements.
How do I choose a pillow block bearing?
Start with the shaft diameter, then check load, RPM, mounting dimensions, alignment, locking method, lubrication and operating environment.
Are pillow block bearings self-aligning?
Some pillow block bearing designs use self-aligning inserts that can accommodate limited shaft or housing misalignment. Not every pillow block bearing has this feature.
What is the difference between a pillow block bearing and a standard bearing?
A standard bearing is generally the bearing component itself, while a pillow block unit combines a bearing insert with a housing and mounting arrangement.
What shaft sizes are available for pillow block bearings?
Pillow block bearings are available for a wide range of shaft sizes, from small shafts to large industrial applications. The exact sizes depend on the bearing series and manufacturer.
How are pillow block bearings mounted?
They are generally mounted to a flat machine surface using bolts through the housing. The bearing insert is then secured to the shaft using the appropriate locking arrangement.
How often should pillow block bearings be lubricated?
The lubrication interval depends on the bearing type, speed, load, temperature and operating environment. Always follow the recommended lubrication requirements for the specific bearing.
Can pillow block bearings handle heavy loads?
Yes, certain pillow block bearing units are designed for heavy loads. The correct unit should be selected based on the actual radial, axial and shock loads.
Can pillow block bearings be used outdoors?
Yes, suitable pillow block bearings can be used outdoors. However, sealing, corrosion protection, lubrication and environmental exposure need to be considered.
Where can I buy pillow block bearings in Bangalore?
You can contact Kashyap Bearing on SP Road, Bangalore for pillow block bearing requirements. Share the bearing number, shaft dimensions or application details so the appropriate unit can be identified.
Final Word
Pillow block bearings provide a convenient way to support rotating shafts while combining the bearing and housing into a single mounting unit.
From standard pillow blocks and self-aligning units to flanged, take-up, cartridge and split housing arrangements, different types are designed for different machine configurations.
Choosing the right pillow block isn't simply about matching the shaft diameter.
Before purchasing, check the shaft size, bearing dimensions, mounting holes, radial load, axial load, operating speed, alignment, locking method, lubrication and operating environment.
If you're replacing an existing unit, start with the complete bearing number and take measurements of the mounting arrangement. For a new application, provide the supplier with the machine's load, RPM, shaft size and operating conditions.
And if you're unsure which pillow block bearing is right for your application, Kashyap Bearing can help you narrow down the available options. Share your bearing number, dimensions or application requirements with the team before purchasing so you can select a pillow block bearing that actually matches your machine rather than choosing one based only on shaft size.
Comments