Timken52387W-3Tapered Roller Bearing Cone, 3.8750 in Keyed Bore, 1.4220 in Cone Width, Class 3 Precision, Case-Carburized Steel

Product Description

What this part is

A Timken 52387W-3 single tapered roller bearing cone in Class 3 precision, with a keyway machined in the bore. Brand: Timken. Part Number: 52387W-3. Base Number: 52387W. Series: Timken imperial TS tapered single, 52000 sequence. Bore: 3.8750 in / 98.425 mm, keyway in bore. Cone Width: 1.4220 in. Bore Type: Straight, keyed. Locking Method: Keyed bore. Number Of Rows: 1. Rolling Elements: Tapered rollers. Precision Class: Timken Class 3. Material: Case-carburized steel. Cage Type: Stamped, roller-guided. Cage Material: Steel. Closure Type: Open. Item Weight: 2.50 lbs. Operating Temperature: -54 °C to +120 °C. Design Units: Imperial (inch).

Decoding the designation

52387: Timken imperial TS cone number, 3.8750 in bore, mating the 52618 cup. W: keyway in the cone bore, so the cone is driven by a key. -3: Timken precision Class 3, tighter bore, width and runout than the standard Class 4 / K grade. Cartons often stamp the class as a leading asterisk, so the part also reads 52387W *3 and 52387W3.

What these specs mean in practice

A keyed cone belongs where the bearing transmits or resists torque about the shaft, or where the assembly is broken down often enough that a heavy interference fit would mark the shaft. The key also fixes the cone’s angular position, which matters on ground or indexed shafts: the key carries the drive and a lighter fit carries the location. Class 3 tightens bore, width and runout so the axial setting is repeatable, which is what heavy gearing and mill positions need.

Quantity and configuration

Cone only — inner ring, rollers and cage as one non-separable unit. Unit Quantity: 1 Pc. Mating cups: Timken 52618, 52637 and 52637B. The 52387W/52618 assembly measures 3.8750 in bore x 6.1875 in outside diameter x 1.4375 in overall width (T), with a 1.0313 in cup width.

Bore form

Straight bore with a keyway. Bore: 3.8750 in / 98.425 mm. The keyway is the feature that separates this cone from a plain 52387, which shares the same envelope on a plain straight bore.

Interchange guidance

The standard assembly is 52387W/52618. Inch tapered roller numbering is an industry standard rather than a brand code, so Koyo 52387W, NTN 52387W and SKF 52387 describe the same envelope; the keyed executions carry the W. A plain 52387 is the same envelope on a plain straight bore and is carried here as a dimensional reference with that difference named. A plain 52387W without the -3 suffix is the same keyed cone in standard Class 4 / K precision and substitutes where the tighter class is not specified.