Timken42381-3Tapered Roller Bearing Cone – 3.8125 in Bore, 1.1406 in Width, Class 3, K Factor 1.19

Product Description

What this part is:

Timken 42381-3 tapered roller bearing cone. This is the inner ring with its tapered roller set and cage, the rotating half of a Timken TS single-row inch tapered roller bearing, built to Class 3 precision. Bore Diameter: 3.8125 in (3-13/16 in, 96.838 mm). Overall Width: 1.1406 in (28.971 mm) inner ring width. Item Weight: 3.77 kg (8.32 lb). Dynamic Load Rating: 193,000 N (43,400 lbf) at C1. Static Load Rating: 241,000 N (54,300 lbf). Precision Class: Class 3. Rolling Elements: Tapered Roller. Number Of Rows: 1. Bore Type: Straight. Cage Type: Pressed. Bearing Material: case-carburized alloy steel. Design Units: Imperial. Series: 42000. Base Number: 42381.

Decoding the designation:

42381 — a cone number in Timken’s inch 42000 tapered roller series, fixing the 3.8125 in bore and the 1.1406 in inner ring width.

-3 — Precision Class 3, also written *3 and #3. A tighter tolerance than standard, giving lower running vibration and closer location of the shaft. The class changes tolerance only; bore, width, raceway angle and load ratings are those of the 42381.

What these specs mean in practice:

K Factor: 1.19. A K factor near 1.2 is a steep taper: the raceway angle puts a large share of the capacity into thrust, so the bearing suits a position carrying heavy combined radial and axial load rather than pure radial duty.

Dynamic Load Rating: 193,000 N (C1, at 1 million revolutions, ISO method). Dynamic Radial Load Rating at 90 million revolutions (C90): 50,100 N. Dynamic Axial Rating at 90 million revolutions (Ca90): 42,200 N — 84 per cent of the radial figure, which is the numerical expression of that steep taper. Static Load Rating: 241,000 N.

G1 Factor: 129.7. G2 Factor: 37.2. Geometry Factor (Cg): 0.139, the geometry constant for the lubrication life adjustment factor a3l.

Mounting data:

Maximum Shaft Fillet Radius: 0.140 in (3.600 mm) — the largest fillet the shaft shoulder may carry and still be cleared by the cone corner. Shaft Backing Shoulder Diameter, frontface (da): 4.13 in (105 mm). Shaft Backing Shoulder Diameter, backface (db): 4.41 in (112 mm). Effective Centre Location: 0.12 in (3 mm), measured outside the cone backface. Cage Location relative to backface (Aa): 0.10 in. Cage Location relative to frontface (Ab): 0.14 in.

Quantity and configuration:

Unit Quantity: 1 Pc. Cone only — inner ring, rollers and cage. The matching cups are the Timken 42587 and 42584.

Interchange guidance:

42381 is an inch tapered roller cone number on the common industry dimensional standard, so a 42381 from another inch-series maker carries the same bore, width and raceway angle. The Class 3 tolerance is a Timken execution, so a standard-tolerance 42381 matches the envelope but not the running accuracy. Cross-references: Koyo 42381, NTN 4T-42381, NSK 42381, Bower / BCA 42381, Fersa 42381.