Pillow Block & Flange Bearings
AST Bearings supplies Shuster Brand f pillow block bearings and flange bearing units designed to keep rotating shafts securely aligned and supported in demanding industrial environments. Whether you need a standard pillow block bearing for horizontal shaft support or a flange mounted bearing for perpendicular mounting surfaces, our catalog covers cast iron, thermoplastic, and stainless steel housing options to match your application.
Read more about each type of pillow block bearing and flange bearing below.
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Pillow Block Bearing vs. Flange Bearing: What's the Difference?
A pillow block bearing (also called a plummer block) is a mounted bearing unit designed for radial loads acting parallel to the mounting surface, making it ideal for horizontal shaft support. A flange bearing, by contrast, is mounted through a flange housing perpendicular to the shaft axis and is available in 2-bolt, 3-bolt, and 4-bolt configurations to accommodate different load and space requirements. Both are mounted bearing units built around the same core components (housing, insert bearing, seals, and locking collar), but the mounting orientation determines which is right for your application.
Need help deciding? Our engineering team can help match the correct pillow block or flange bearing to your shaft orientation, load, and speed requirements.
Pillow Block Bearing Types
Insert Bearings for Mounted Bearings
AST offers two types of insert bearings designed for use in mounted bearing units. Simplistically, they are divided by size with the smaller, miniature insert bearings called "collar clamp ball bearings" and the larger ones called the ER Series insert bearings:
Flanged Mounted Block Bearing Units
While other configurations are available from AST Bearings upon special order, the most common flanged mounted block bearing units are either two-bolt or four-bolt designs. Small two-bolt designs are commonly called flangettes but are of a totally different construction and design to the heavier duty Two-bolt flange series. Click on the hyperlinks of the below to learn more each type of flanged mounted bearing units:
Axially Opposed Mounted Bearing Units
While the flanged mounted bearing units above have the axial/shaft perpendicular to the mounting surface, the units below have the shaft running parallel to the mounting surface. Click on each of the series below to learn more about each type:
Frequently Asked Questions
What is a pillow block bearing?
A pillow block bearing is a mounted bearing unit consisting of a housing (cast iron, thermoplastic, or stainless steel) with an insert bearing mounted inside. It supports a rotating shaft on a horizontal surface, allowing radial loads while keeping the bearing securely aligned and protected from contamination.
What is the difference between a pillow block bearing and a flange bearing?
A pillow block bearing mounts flat on a surface for horizontal shaft support, while a flange bearing mounts through a flange perpendicular to the shaft, commonly in 2-, 3-, or 4-bolt configurations. Both use similar internal components but differ in mounting orientation and application.
What are the different types of flange bearings?
Flange bearings are categorized by bolt pattern: 2-bolt flanges (compact, lighter loads), 3-bolt flanges (space-constrained mounts), and 4-bolt flanges (higher load capacity). Flangette units are a smaller, lighter-duty variation of the 2-bolt design, often used for lower-load, space-limited applications.
What materials are pillow block and flange bearings made from?
Pillow block and flange bearing housings are commonly made from cast iron for standard-duty use, thermoplastic for lightweight and corrosion resistance, and stainless steel or nickel-plated housings for wash-down and corrosive environments like food & beverage or medical applications.
How do I choose the right pillow block or flange bearing?
Selecting the right unit depends on shaft orientation, load direction, speed, and environment. Horizontal shafts typically use pillow blocks; perpendicular mounting surfaces call for flange bearings. Consider housing material and bolt configuration based on your industry's contamination, corrosion, or load requirements.
Flanged Ball Bearings (Non-mounted)
Besides the mounted flanged bearing units above, many ball bearings have flanges as options to their configurations to aid in mounting and positioning. This is especially true for miniature and instrument bearings but applies to other ball bearing types. To see what AST offers in flanged ball bearings (non-mounted), please visit the links below:
How to Select Pillow Blocks, Flanges, Take Up Units, Mounted Bearings, and Bearing Inserts
If you need help in selecting the best products for your particular application, please remember that design engineering and application assistance are available from AST as part of our value-added services designed to make your job easier.
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