FafnirRCSM1/2Cylindrical Cartridge Block Ball Bearing Unit, 1/2 in Bore, 2.531 in Cartridge OD, Eccentric Locking Collar

Product Description

What this part is

A Fafnir RCSM1/2 cylindrical cartridge block mounted ball bearing unit for a 1/2 in shaft. A moulded one-piece cartridge carries an RA008RR extended-inner-ring bearing with contact seals on both faces and an eccentric self-locking collar. The cartridge outside diameter is 2.531 in, so the unit drops into a bored tube or a cartridge saddle.

Decoding the designation

RCSM is the Fafnir cylindrical cartridge block series with an eccentric locking collar. The trailing 1/2 is the shaft size in inches. In the bearing number RA008RR, RA marks the extended-inner-ring series supplied with a collar, 008 encodes the 8/16 in – that is 1/2 in – bore, and RR denotes contact seals on both faces. The absence of a G prefix marks the bearing as pre-greased with no relubrication path.

Housing style and mounting envelope

Housing construction: cylindrical cartridge block, moulded synthetic rubber cartridge
Cartridge outside diameter D: 64.3 mm / 2.531 in
Cartridge width M: 34.9 mm / 1.375 in
Dimension A: 25.4 mm / 1 in
Dimension B1: 28.6 mm / 1.126 in
Dimension d1: 28.6 mm / 1.126 in
Dimension S1: 22.1 mm / 0.87 in
Dimension T: 12.7 mm / 0.5 in

What these specs mean in practice

A cartridge block locates by its cylindrical outside diameter rather than by bolts, so the mounting bore diameter and cartridge width are the two fields a frame is matched on. The resilient cartridge absorbs a degree of shaft misalignment and damps vibration, and its own radial capacity governs the installed rating: Timken publishes a housing radial load rating of 200 lb against a bearing dynamic rating of 2 380 lbf, so the cartridge sets the practical ceiling in this unit. The eccentric collar locks to the shaft by cam action, turned in the direction of shaft rotation and then set with its cup-point setscrew, so drive torque tends to tighten it. The extended inner ring provides the collar seat and lets the unit run on plain commercial shafting.

Published ratings and mounting data

Shaft size d: 1/2 in (12.7 mm)
Bearing number: RA008RR
Bearing type: single-row ball, extended inner ring
Housing radial load rating: 880 N / 200 lb
Dynamic load rating: 10 700 N / 2 380 lbf
Static load rating: 4 700 N / 1 070 lbf

Quantity and configuration

Complete cartridge unit: moulded cartridge, bearing and eccentric locking collar. 1 Pc.

Fitting notes

The cartridge is pressed into a 2.531 in bore or clamped in a cartridge saddle, square to the shaft axis. The collar setscrew is tightened after the collar has been cammed round in the direction of shaft rotation. Lubrication is the factory grease charge for the life of the unit.

Interchange guidance

The bearing inside this cartridge is the Fafnir RA008RR. RCJT1/2 and RAS1/2 cover the same 1/2 in shaft on two-bolt flange and two-bolt pillow block housings; those are related sizes with a different mounting method and a different installed load rating.