TORRINGTONIR-12814848Needle Roller Bearing INNER RING ONLY — 8.000 in Bore × 9.250 in OD × 3.000 in Wide Hardened and Ground Steel Raceway Sleeve (No Rollers, No Cage) for HJ-14817848

Product Description

What this part is

This is an inner ring — a hardened, ground and precision-finished steel sleeve that presses onto an 8.000 in shaft and provides the inner raceway for a Timken/Torrington HJ-series heavy-duty cylindrical roller (needle roller) bearing. It is not a complete bearing. There are no rollers and no cage in this part. It is the mating half of the HJ-14817848 roller-and-cage assembly, and Timken’s own catalogue record for HJ-14817848 lists IR-12814848 as its designated inner ring.

HJ-series bearings are built this way on purpose. If the shaft can be hardened and ground to raceway quality, the HJ runs directly on the shaft and no inner ring is needed. If it cannot — a soft shaft, a worn shaft, a shaft that must be repairable in the field — the IR inner ring becomes the sacrificial raceway. Rings wear out and get replaced; shafts do not.

Decoding the designation

Torrington encodes IR and HJ dimensions directly in sixteenths of an inch, three digits at a time:

128 → 128/16 = 8.000 in bore148 → 148/16 = 9.250 in outside diameter48 → 48/16 = 3.000 in width
The same scheme reads its partner HJ-14817848 as 9.250 in bore (148), 11.125 in OD (178) and 3.000 in width (48) — and 9.250 in is exactly the OD of this ring. That is the arithmetic proof that the two parts are a matched pair.

Correcting the source data

Two errors in the previous listing have been fixed:

The outside diameter was stated as 9-1/2 in. It is 9-1/4 in (9.250 in / 234.95 mm). Both the part-number arithmetic (148/16) and Timken’s own published shaft diameter Fw for the mating HJ-14817848 confirm 9.250 in.The part was described as a needle roller bearing. It is an inner ring only. A buyer expecting a complete bearing and receiving a plain sleeve is a dispute, so this is stated plainly rather than buried.

What these specs mean in practice

The ring’s 3.000 in width matches the roller assembly’s width, so it carries the full roller path with no overhang. Because it is a press fit on the shaft, the ring effectively sets the shaft diameter the bearing sees: fit an IR ring and your 8.000 in shaft becomes a 9.250 in raceway. That changes surface speed at the raceway and it changes the shoulder and retention arrangement you need at each end of the ring. Plan the assembly around the ring, not around the bare shaft.

Published data for the mating bearing

Timken publishes these for the HJ-14817848 roller assembly that runs on this ring, and they are the numbers that size the joint:

Dynamic radial load rating C₁ (1 million revolutions): 599,000 N / 145,000 lbfStatic radial load rating C₀: 1,350,000 N / 326,000 lbfThermal speed rating, oil: 1,300 rpm; grease: 1,200 rpmGeometry factor Cg: 0.1885 (stated for the bearing without inner ring)Housing shoulder diameter Da: 266.70 mm / 10.500 inMeets Military Standard MS 51961
Load ratings and speed for the inner ring in isolation are not separately published, because a raceway sleeve has no independent rating — it is rated as part of the assembly.

Fitting notes

Timken’s guidance for this bearing family: use a clearance fit on the outer ring where the housing is stationary relative to the load, and a tight transition fit where the housing rotates relative to the load. Consult Timken before using it in an oscillating application, where low radial clearance is a real concern. The unmarked end of the outer ring goes against the housing shoulder so the maximum allowed housing fillet is cleared. Published fits for the mating surfaces: clearance fit 9.2488–9.2500 in on the ring OD, and tight transition 9.2468–9.2480 in.

Interchange guidance

Also written IR12814848, IR 128 148 48, IR-128-148-48. Torrington needle roller bearings became part of The Timken Company, so current-production equivalents are catalogued under Timken — a search for “Torrington” alone will miss them. Buy this ring together with an HJ-14817848 (Timken alternate designation 6673M) if you need the complete joint; the two are sold separately and neither works without a raceway on the other side.