The Timken Fafnir cast iron pillow block with eccentric collar locking is the go-to mounted bearing unit for industrial, agricultural, and material handling applications. Available across 6 housing series with shaft sizes from 1/2″ to 3-15/16″, these units combine Timken’s precision insert bearings with rugged cast iron housings for reliable, long-lasting performance.

Why Eccentric Collar Locking?

Unlike set screw designs that can mar the shaft or loosen under vibration, the eccentric collar uses a cam-action locking mechanism that grips the shaft concentrically with a single wrench. This delivers superior holding power, easier installation, and cleaner shaft removal — no set screw damage, no allen wrenches, no headaches. Simply rotate the collar in the direction of shaft rotation and tighten the locking bolt.

Housing Series Comparison:

• RAK — Standard Duty: The workhorse pillow block. Standard base height, versatile mounting for general industrial and agricultural drives.
• RAKH — Heavy Duty: Reinforced housing with heavier wall sections for high-load applications, conveyors, and demanding environments.
• RAKHL — Heavy Duty, Low Base: Same heavy-duty construction as RAKH but with a reduced base height for tight-clearance mounting where shaft centerline must be kept low.
• RAO — Open End: Open housing design allows the bearing to be removed or replaced without dismounting the housing. Ideal for maintenance-intensive applications.
• RAS — Standard with RR Seal: Standard pillow block equipped with Timken’s premium RR contact seal for superior contamination protection in dusty or wet environments.
• RASC — Compact: Narrow-profile housing for space-constrained installations. Shorter overall length while maintaining full load capacity.

Engineering Highlights:

• Self-Aligning: Spherical OD on the insert bearing allows up to ±2° static misalignment, compensating for shaft deflection and mounting irregularities
• Seal Options: Standard felt labyrinth seal; RR-series units feature heavy-duty contact rubber seals for demanding environments
• Load Ratings: Dynamic load ratings from approximately 3,200 lbf (small shafts) to over 30,000 lbf (large shafts), depending on series and size
• Lubrication: Pre-lubricated with Timken premium grease; re-greasable via zerk fitting on housing
• Temperature Range: −20°F to +220°F continuous operation (standard seals)
• Housing Material: ASTM A48 Class 30 gray cast iron, corrosion-resistant primer finish
• Shaft Sizes: 1/2″ through 3-15/16″ in fractional-inch increments

Key Features at a Glance:

• Eccentric collar locking — single wrench, no set screws, no shaft damage
• 6 housing series to match any application requirement
• Self-aligning insert bearings compensate for misalignment
• Cast iron housings with precision-machined bores
• Pre-lubricated and re-greasable for extended service life
• 222 configurations covering shaft sizes from 1/2″ to 3-15/16″
• Direct replacement for competitive eccentric collar pillow blocks