The Timken Fafnir cast iron pillow block with set screw locking is the industry-standard mounted bearing unit for conveyors, fans, agricultural equipment, and general industrial applications. Available across 7 housing series with shaft sizes from 1/2″ to 4-7/16″, these units pair Timken’s precision insert bearings with rugged cast iron housings for dependable, long-lasting performance.

Why Set Screw Locking?

Set screw pillow blocks use two hardened socket-head set screws that grip directly against the shaft. This is the simplest and most widely used locking method in the industry — no special tools beyond a standard hex key, works equally well in both rotation directions, and provides reliable holding power for the vast majority of applications. Set screw locking is the default choice when shaft damage from the screws is acceptable and eccentric collar or adapter sleeve mechanisms are not required.

Housing Series Comparison:

• SAK — Standard Duty: The workhorse set screw pillow block. Standard base height, versatile mounting for general industrial and agricultural drives.
• SAL — Low Base: Standard-duty construction with a reduced base height for tight-clearance mounting where shaft centerline must be kept low.
• SAOL — Open, Low Base: Open housing design with low base height. Allows bearing removal or replacement without dismounting the housing — ideal for maintenance-intensive applications with limited vertical clearance.
• SAS — Standard with RR Seal: Standard pillow block equipped with Timken’s premium RR contact seal for superior contamination protection in dusty or wet environments.
• YAK — Y-Series Standard: Uses the industry-standard YA/YAS insert family. The most popular set screw pillow block for new equipment design, with wide interchangeability across manufacturers.
• YAS — Y-Series General Purpose: Y-series insert in a general-purpose housing. Broad size range including metric bores, SGT (re-greasable) variants, and specialty shaft sizes.
• YASM — Y-Series Miniature: Compact, narrow-profile Y-series pillow block for light-duty and space-constrained installations.

Engineering Highlights:

• Self-Aligning: Spherical OD on the insert bearing allows up to ±2° static misalignment, compensating for shaft deflection and mounting irregularities
• Set Screw Retention: Two hardened socket-head set screws at 120° apart lock the inner ring to the shaft — works in both rotation directions
• Seal Options: Standard felt labyrinth seal; RR-series (SAS) units feature heavy-duty contact rubber seals for demanding environments
• Load Ratings: Dynamic load ratings from approximately 2,380 lbf (small shafts) to over 39,000 lbf (large shafts), depending on series and size
• Lubrication: Pre-lubricated with Timken premium grease; re-greasable via zerk fitting on housing. SGT variants feature extended re-lubrication capability
• 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 4-7/16″ in fractional-inch, plus metric bores from 17mm to 75mm

Key Features at a Glance:

• Set screw locking — two set screws, standard hex key, both rotation directions
• 7 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
• 148 configurations covering shaft sizes from 1/2″ to 4-7/16″
• Direct replacement for competitive set screw pillow blocks