FafnirMUB1/2Replacement Insert Bearing Unit for SA / SAD / SADD Pillow Blocks, 1/2 in Bore, Self-Aligning

Product Description

What this part is

A Fafnir MUB1/2 replacement bearing unit for a 1/2 in shaft, supplied with its locking collar, snap ring and labyrinth seal shield. Insert unit only, no pillow block. The matching housings are the Fafnir SA, SAD and SADD series direct-mounted pillow blocks.

Decoding the designation

MUB is the Fafnir replacement bearing unit series for SA, SAD and SADD type pillow blocks; the trailing 1/2 is the shaft size in inches. The SA series it serves is a direct-mounted pillow block built around a single-labyrinth-sealed, externally self-aligning wide-inner-ring bearing, so the MUB unit carries that same spherical outer surface and labyrinth arrangement. The SAD designation covers the same block furnished with a dust seal collar, and SADD adds a dust seal collar plus a rear dust seal.

What these specs mean in practice

An external self-aligning bearing runs its spherical outer surface against a matching internal spherical surface in the housing, so shaft-to-housing angular misalignment is taken up at the seat rather than in the ball path. That is what makes a direct-mounted pillow block tolerant of an out-of-true frame. The locking collar seats on the extended inner ring and lets the unit run on plain commercial shafting rather than a ground journal. The labyrinth shield forms a non-rubbing path against the collar face, so it excludes coarse contamination without adding seal drag.

Published specifications

Bore: 1/2 in (12.7 mm)
Bearing type: single-row ball, wide inner ring, external self-aligning spherical outer surface
Closure: single labyrinth seal shield
Outer-ring retention: snap ring
Locking: collar on the extended inner ring
Housing series served: SA, SAD, SADD pillow blocks

Quantity and configuration

Insert bearing unit, locking collar, snap ring and shield. 1 Pc.

Fitting notes

The unit is entered into the spherical seat of an SA-series pillow block, rotated square to the shaft axis, and retained by its snap ring. The collar setscrew is tightened last, with the shaft in its running position.

Interchange guidance

MUB is the replacement unit for the SA, SAD and SADD pillow block series. MUA is the equivalent series for DSA and DSADD double pillow blocks, MUOB serves the heavier SAO, SAOD and SAODD blocks, and PSM-S or PSM-TS serve the SAL blocks; those are the replacement units for different housing families rather than substitutes for this one.