NA4868 bearing: complete specifications & equivalents
The NA4868 is a ISO 1206 radial bearing sized 340 x 420 x 80 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 340 mm |
| Outer diameter D | 420 mm |
| Width B | 80 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 616 kN |
| Basic static load rating C0 | 1960 kN |
| Fatigue load limit Pu | 183 kN |
| Reference speed (thermal) | 1000 rpm |
| Limiting speed (mechanical) | 1200 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 24000 g |
| Manufacturer designation | NA 4868 |
| Standard | ISO 1206 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & NA-48-series range
| Bore d | 13.386 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 3.15 in |
| ISO bore code | 68 |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in NA-48-series | 110 mm |
| Largest outer diameter in NA-48-series | 480 mm |
| Width range across NA-48-series | 30–100 mm |
| Bore position in NA-48-series (smallest first) | 17 of 19 |
| Bore above smallest NA-48-series size | 230 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NA4868 model number is decoded
SKF lists NA 4868 in the dimension series 48 needle roller bearings with inner ring with boundary dimensions 340×420×80 mm: an inner ring turns on the shaft while the flanged outer ring carries the needle roller complement in the housing. The NA 4868 code gives bore 340 mm and width 80 mm explicitly; unlike the RNA/NK families the shaft only needs a standard k5/j5 seat because the hardened inner ring is the raceway. Execution notes: the inner ring is ground on bore and raceway, so the shaft seat is a normal k5/j6; the flanged outer ring needs no housing shoulder, and NA 49 2RS executions add seals with a wider outer ring. Selection arithmetic: C 616 kN against C0 1960 kN gives a C0/C ratio of 3.18, and the 183 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Because the inner ring is separable, mount it first against its shoulder, then slide the outer ring and roller set over it — the order avoids forcing rollers across the shaft threads or burrs.
Typical equipment & failure modes
Common applications
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
- conveyor roller ends and return rollers
- agricultural implement pivots and cutter heads
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- cage pocket wear and roller skew after sustained operation with too little radial preload
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- false brinelling of standby equipment under external vibration
- inner-ring bore fretting on a loose shaft seat, migrating hard particles into the rolling contact
Selection pitfalls — read before you substitute
- Above 50 mm bore, thermal growth matters: the 340 mm inner ring or journal grows with temperature faster than the housing, and the small clearance of a needle roller contact leaves little reserve — check running clearance hot, not just at assembly.
- Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- The 616/1960 kN ratings and 24000 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 648); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What are the dimensions and ratings of the NA 4868?
A NA 4868 measures 340 mm bore/Fw × 420 mm outside diameter × 80 mm width (13.386 × 16.535 × 3.15 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 616 kN, static C0 1960 kN, fatigue limit Pu 183 kN, limiting speed 1,200 r/min, reference speed 1,000 r/min, mass about 24000 g.
How is the NA 4868 designation read?
The letters mark a machined-ring needle roller bearing with inner ring: 340 mm bore, 80 mm width, 420 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Can the NA 4868 run on an unhardened shaft?
Yes — that is the point of this family. The NA 4868 carries its own hardened, ground inner ring on a 340 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
How should the NA 4868 be mounted?
Mount the inner ring on the 340 mm seat first (induction heat, max 120 °C, or press), then fit the flanged outer ring into the H7 housing bore. Verify free rotation and, for 2RS executions, check the wider outer ring against the housing depth.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.4 machined rings with flanges, with an inner ring on 2026-09-26. Read our editorial & correction policy.