Timken52375-3Tapered Roller Bearing Cone 3-3/4 in Bore x 1.4219 in Wide, Timken Class 3 Precision

Product Description

What this part is

A Timken 52375-3 tapered roller bearing cone — the inner ring complete with its tapered rollers and cage, 3-3/4 in bore and 1.4219 in wide, produced to Timken Class 3 precision. The cone is the half of a tapered roller bearing that goes onto the shaft.

Quantity and configuration

1 Pc. Cone only. The matching cup is the Timken 52639.

Decoding the designation

52375 is the cone number, which fixes the bore, the cone width and the raceway angle together. The trailing 3, written variously as -3, *3 or #3, is Timken precision Class 3 — a tighter grade than Class 2 and tighter again than the standard commercial class, held on bore, raceway form and running accuracy.

What these specs mean in practice

Class 3 is specified where shaft runout and repeatable bearing setting matter: machine tool spindles and tables, printing and converting cylinders, gear inspection stands, and any position where a general-purpose cone leaves too much scatter in the set clearance. The cone assembly is a unit in service — the inner ring, rollers and cage are not separable and the rollers are matched to that ring.

Fitting notes

The cone goes onto the shaft as a press fit, driven or pressed on the inner ring back face only. Setting is done after both races are seated, by moving one race axially against the other to establish the intended end play or preload, which on a Class 3 bearing is set to a tighter band than on a standard-class equivalent.

Two-row service

The same cone is catalogued as NA52375 when it is furnished for two-row or TDO service, where a pair of cones runs against a single double cup.

Interchange guidance

A cone marked 52375 from another tapered roller bearing maker shares the envelope and the same 52639 mating cup, but a plain 52375 is standard class: it is a related part rather than a substitution where the Class 3 grade is the reason for the specification. The 52618 and 52630X are alternative cups for this same cone, differing in outside diameter.