Timken46790A-3Single Row Tapered Roller Bearing Cone Only, 6-1/2 in / 165.1 mm Bore, 1.5625 in Inner Ring Width, Precision Class 3, K Factor 1.52 — Cup Not Included

Product Description

Cone without cup — read this first

This listing is a cone only. In tapered roller bearing language the cone is the inner ring complete with its tapered rollers and cage; the cup is the separate outer ring the rollers run against. A tapered roller bearing does not become a bearing until both are present. This part fits a shaft, not a housing bore.

It suits a position where the cup is already installed and sound and the rotating half is being replaced. A complete bearing requires this cone plus a 46720 cup.

What this part is

A large inch-series single-row tapered roller cone, 6.5 in / 165.1 mm bore, inner ring width 1.5625 in / 39.688 mm, weight 21.63 lb / 9.812 kg. The ring is stamped 46790A with a *3 class mark, and the original Timken carton is marked PRECISION. Made in USA.

Decoding the designation

46790A is the cone base number in Timken’s inch tapered roller series. The trailing A is a design revision, not a size change.

*3 / -3 is a precision class suffix. Timken applies a numeric class mark to cones held to tighter running and bore tolerances than the standard class, consistent with the PRECISION marking on this carton.

46720 is the mating cup. It is not part of this listing.

What these specs mean in practice

The K factor of 1.52 is the ratio between the bearing’s dynamic radial and dynamic thrust ratings, set by the raceway contact angle. It converts a combined radial-plus-thrust load into an equivalent radial load for a life calculation, and it indicates a design steep enough to carry meaningful thrust rather than a radial-only bearing.

The effective centre location is 0.1 in / 2.5 mm, positive, which places the point where the bearing’s reaction acts just outside the cone backface. On a two-bearing shaft that offset is the support point for bearing spacing and shaft bending calculations; using the physical ring face instead moves both reaction points and yields the wrong bending moment.

The two dynamic ratings are quoted on different bases and are not alternatives. C1 of 68,200 lbf is the load for one million revolutions; C90 of 17,700 lbf is the load for ninety million revolutions. Timken’s inch catalogue quotes C90 because ninety million revolutions is 3,000 hours at 500 rpm, a working-life figure rather than a headline number. C90 should be compared with C90.

Published ratings and mounting data

Bore d: 6.5 in / 165.1 mm.

Inner ring width B: 1.5625 in / 39.688 mm.

Dynamic radial rating C1 (1 million revolutions): 68,200 lbf / 303,000 N.

Dynamic radial rating C90 (90 million revolutions): 17,700 lbf / 78,600 N.

Dynamic axial rating Ca90: 11,600 lbf / 51,600 N.

Static radial rating C0: 143,000 lbf / 635,000 N.

K factor: 1.52.

Effective centre location a: 0.1 in / 2.5 mm.

Maximum shaft fillet radius: 0.310 in / 7.900 mm.

Shaft backing shoulder diameter, frontface da: 6.85 in / 174 mm; backface db: 7.44 in / 189 mm.

Cage location Aa 0.13 in / 3.3 mm, Ab 0.12 in / 3 mm.

Geometry factors G1 572, G2 154; Cg 0.143.

Weight: 21.63 lb / 9.812 kg.

Mounting data

Cone and cup are lapped as a matched design family, so a 46790A cone is dimensioned to run against a 46720 cup. Maximum shaft fillet radius is 0.310 in / 7.900 mm and the shaft backing shoulder diameter falls between da 6.85 in / 174 mm and db 7.44 in / 189 mm. Single-row tapered roller bearings are not preset; the assembled bearing is adjusted to a specified endplay or preload set by the equipment manufacturer.

Interchange guidance

Written variously as 46790A, 46790-A, 46790 A, 46790A-3, 46790A*3 and 46790A/3. Mating cup 46720 (also 46720-B in some listings); double cup form 46720CD for TDO arrangements. Complete single-row bearing is commonly quoted as 46790A/46720. Cross-reference by dimension against other makers: 165.1 mm bore, 39.688 mm inner ring width.