Torrington32SF52Radial Spherical Plain Bearing 3-1/4 x 5-1/8 in, Unsealed Steel-on-Steel, Single-Fractured Outer Ring, MoS2 Coated, Relubricatable Through Either Ring

Product Description

What this part is

The Torrington 32SF52 is a radial spherical plain bearing, Type SF: two rings, no rolling elements. Bore: 3.2500 in (82.55 mm). Outside Diameter: 5.1250 in (130.18 mm). Inner Ring Width: 2.8437 in / 2-27/32 in (72.23 mm). Outer Ring Width: 2.4375 in / 2-7/16 in (61.91 mm). Rolling Elements: none, plain sliding spherical contact. Closure: unsealed. The inner ring carries a convex spherical outer surface and the outer ring a matching concave bore, which gives very high load capacity in a short envelope and absorbs shaft misalignment. The inner ring stands proud of the outer ring on both faces, and that projection is what lets it tilt inside the housing.

Decoding the designation

32 — the Torrington series number, an approximate bore reference of about 3.2 in.

SF — radial spherical plain type with a single-fractured outer ring. The outer ring is split axially in one place so the rings can be assembled, and a snap ring holds the halves together for handling and installation.

52 — the exact bore in sixteenths of an inch. 52/16 gives 3.250 in.

No seal suffix — the unsealed execution. 32SF52SS carries synthetic resin seals and 32SF52TT reinforced nitrile rubber lip seals, on the same envelope under their own part numbers.

Construction and materials

Material: through-hardened, precision ground steel inner and outer rings, phosphate treated with a molybdenum disulphide (MoS2) coating on the sliding surfaces. The coating cuts friction on start-up and through the slow reversals this bearing is built for, and it reduces the ground radial internal clearance by up to 0.002 in (0.05 mm). Axial internal clearance runs at approximately three times the radial figure. Steel-on-steel is the high-capacity, wear-resistant construction, and it is designed to be regreased on a schedule.

Lubrication

Lubricant: grease or oil. The SF series carries lubrication holes and grooves in both the inner and the outer ring, so lubricant reaches the sliding surfaces through either the shaft or the housing.

Load rating basis

Timken rates the SF series on sliding contact stress rather than on rolling fatigue. Dynamic Load Rating Basis: a maximum sliding contact stress of 85 MPa (approximately 12,300 psi), calculated on the radially projected area of the inner ring bore. Radial capacity is the primary rating; thrust capacity on this radial type is a quarter of the corresponding radial figure.

Mounting data

Preferred Shaft Tolerance: g6 to ANSI B4.1. The outer ring is fractured in one place and held by a snap ring, so the housing bore carries part of the structural load and restores the ring to roundness once the bearing is seated. Housing bore dimensions published by Timken apply to steel housings.

What these specs mean in practice

A sliding spherical contact carries far more load per unit of envelope than a ball or roller bearing of the same size, and it tolerates misalignment that would destroy a rolling bearing. The trade is speed: this is a heavy, slow, oscillating-duty bearing rather than a continuous high-speed one.

Interchange guidance

Torrington spherical plain bearings are Timken product; The Torrington Company and Fafnir were both consolidated into The Timken Company, and Timken lists 32SF52 as a Type SF spherical plain bearing. The same 3-1/4 in bore envelope is searched under the RBC/Heim B52-L designation and the SKF-style GE82, GE82ZO, GEZ304DO and GEZ304ES numbers. The sealed equivalents of those numbers, and 32SF52SS and 32SF52TT, are the sealed executions.

Application types

Hydraulic cylinder pivots and clevises, linkages and levers, crane and hoist sheave pivots, construction and agricultural equipment pins, press and forging machinery, dam and lock gates, and rocker arms.