TimkenNA46791Tapered Roller Bearing Cone, 6-1/2 in Bore, 46700 Imperial Series, Two Pieces

Product Description

WHAT YOU ARE ACTUALLY BUYING

A tapered roller bearing splits into two separable halves: the cone (the inner ring with its rollers and cage) and the cup (the outer ring). This listing is cones only. A cone on its own will not run – it needs a mating cup from the 46720 family, and that cup is a separate part number and a separate purchase. Two pieces are supplied under this listing.

WHAT THE NA PREFIX MEANS FOR SOURCING THIS PART:
Be aware of this before you order, because it affects what can and cannot be verified. NA46791 does not appear in Timken’s current public catalogue. The nearest catalogued numbers in the same family are the 46790 single cone, which shares the 6-1/2 in bore, and the 46791DW double cone, also 6-1/2 in bore. NA-prefixed Timken tapered numbers are typically engineered or special-order variants produced to a customer specification rather than stock catalogue items, which is precisely why the public data thins out.

The practical consequence: the bore is 6-1/2 in, taken from the part number family and the ring, and the series is Timken 46700 imperial. Load ratings, inner ring width, cage type, K factor and abutment dimensions are deliberately NOT quoted on this page. Timken publish none for NA46791, and the figures for 46790 and 46791DW are different parts – borrowing them would give you numbers that look authoritative and are wrong. If you are sizing a position rather than replacing like for like, get the special-order data sheet from Timken against this exact number.

HOW TO CONFIRM FIT BEFORE YOU BUY

For a special-order number this matters more than usual. Measure your shaft seat and compare it against the cone bore. Check the cup you already have in the housing – the cone taper and the cup taper must be a matched pair, and a cone from an NA variant is not guaranteed to run correctly against an off-the-shelf 46720 cup even where the bore and outside diameter agree. Confirm the inner ring width against the axial space in your assembly. If your equipment manual calls out NA46791 by name, this is the number; if it calls out 46790 or 46791DW, it is not.

CONDITION OF THESE PARTICULAR CONES – READ THIS

Used. Made in the USA. The inner races show signs of previous mounting – witness marks from having been pressed onto a shaft. That is a cosmetic and fit indicator, not a running-surface defect, but it tells you these cones have been in service and been removed. Before fitting a used cone, inspect the rollers for spalling, flaking or brinelling, check the cage for cracks and for wear at the roller pockets, and look at the large-end rib for scoring. Used tapered cones are a sound proposition for a non-critical or standby position, or as a spare against a long lead time on a special-order number; they are not the right choice for a critical high-speed or unattended position. Full photographs are provided – use them.

WHY A USED SPECIAL-ORDER CONE IS WORTH LOOKING AT:
This is the honest commercial case. A special-order NA-prefix tapered cone in a 6-1/2 in bore is not something you order on Tuesday and fit on Wednesday – engineered Timken numbers carry lead times measured in months, and the tooling makes a small quantity expensive. Two used cones in hand can be the difference between a planned repair and an extended outage, either as a get-you-running fix or as insurance sitting on the shelf while the new set is on order.

OBSOLESCENCE AND BRAND TRAIL

Timken remain the manufacturer and the 46700 imperial series is current; it is this specific NA variant that has left the public catalogue. Timken absorbed the Fafnir bearing line, so older drawings in the same plant may reference either brand.