NA6901 bearing: complete specifications & equivalents
The NA6901 is a ISO 1206 radial bearing sized 12 x 24 x 22 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 12 mm |
| Outer diameter D | 24 mm |
| Width B | 22 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 16.1 kN |
| Basic static load rating C0 | 23.2 kN |
| Fatigue load limit Pu | 2.75 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 46 g |
| Manufacturer designation | NA 6901 |
| 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-69-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.866 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NA-69-series | 12 mm |
| Largest outer diameter in NA-69-series | 130 mm |
| Width range across NA-69-series | 22–63 mm |
| Bore position in NA-69-series (smallest first) | 1 of 22 |
| Bore above smallest NA-69-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NA6901 model number is decoded
For a 12 mm shaft that cannot be hardened on site, NA 6901 adds a hardened, ground inner ring to the machined needle roller design: envelope 12×24×22 mm per the dimension series 69 needle roller bearings with inner ring plan. In SKF nomenclature the leading letters mark a machined-ring needle bearing with inner ring: figures state 12 mm d and 22 mm B, the 24 mm outside diameter from the dimension series 69 needle roller bearings with inner ring, and the 2RS suffix would add contact seals. Inner rings are separable: order replacement inner rings separately by d×D×B, since the outer ring and roller assembly survive journals that ruin an inner raceway. Minimum load matters: below roughly 0.02·C the rollers skid and smear; preloading the pivot or specifying a heavier execution avoids the glazing that pure oscillation produces on these raceways. 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
- electric motor armature shafts with ground seats
- printing and paper-handling rollers
- gearbox shafts where the journal cannot be hardened on site
- wheel and lever pivots needing a replaceable inner ring
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
- inner-ring raceway spalling after the narrow ring section runs hot with excessive interference
Selection pitfalls — read before you substitute
- On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 24 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Reference and limiting speeds are different limits: the 22,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- Hardness is load capacity: in families without an inner ring the 12 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The 16.1/23.2 kN ratings and 46 g mass are SKF catalogue values transcribed from ch. 7.4 of PUB BU/P1 17000 (PDF table page 638); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Which dimensions does the NA 6901 have?
A NA 6901 measures 12 mm bore/Fw × 24 mm outside diameter × 22 mm width (0.472 × 0.945 × 0.866 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 16.1 kN, static C0 23.2 kN, fatigue limit Pu 2.75 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 46 g.
What does NA 6901 mean in SKF part numbering?
The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 22 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Does the NA 6901 need a hardened and ground shaft?
Yes — that is the point of this family. The NA 6901 carries its own hardened, ground inner ring on a 12 mm seat, so the shaft needs only a normal k5/j6 finish. The inner ring is separable and replaceable.
What mounting mistakes ruin a NA 6901?
Mount the inner ring on the 12 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.