NKI12-16 bearing: complete specifications & equivalents
The NKI12-16 is a DIN 616 radial bearing sized 12 x 24 x 16 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 | 16 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 11.7 kN |
| Basic static load rating C0 | 15.3 kN |
| Fatigue load limit Pu | 1.8 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 33 g |
| Manufacturer designation | NKI 12/16 |
| Standard | DIN 616 |
| 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 & NKI-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.63 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in NKI-series | 5 mm |
| Largest outer diameter in NKI-series | 130 mm |
| Width range across NKI-series | 12–40 mm |
| Bore position in NKI-series (smallest first) | 6 of 30 |
| Bore above smallest NKI-series size | 7 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NKIA5901 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×16 mm envelope, but catalogue C/C0 differ between the executions (11.7/15.3 vs 8.09/9.65 kN) — boundary dimensions match, not a load-rating equivalent. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the NKI12-16 model number is decoded
For a 12 mm shaft that cannot be hardened on site, NKI 12/16 adds a hardened, ground inner ring to the machined needle roller design: envelope 12×24×16 mm per the machined-ring needle roller bearings with inner ring plan. The designation NKI 12/16 tells you the envelope — 12×24×16 mm — and the family tells you the construction: complete bearing, replaceable inner ring, flanged outer ring retaining the needle rollers. The 2RS executions of the 49 series carry contact seals on both faces and a wider outer ring — their B and s dimensions differ from the open execution, so housings must be re-checked before substituting. 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. Mounting: heat or press the inner ring onto the 12 mm k5 seat (max 120 °C), fit the flanged outer ring into the H7 housing bore, and check the 16 mm assembly for free rotation before applying load.
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
- 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
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- rolling-contact fatigue spalling after the rated L10 life
- 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.
- 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 quoted 11.7/15.3 kN ratings are SKF catalogue values for this exact execution (NKI 12/16); ratings can be revised without the order number changing, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the drawing.
- The 11.7/15.3 kN ratings and 33 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
What are the dimensions and ratings of the NKI 12/16?
A NKI 12/16 measures 12 mm bore/Fw × 24 mm outside diameter × 16 mm width (0.472 × 0.945 × 0.63 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 11.7 kN, static C0 15.3 kN, fatigue limit Pu 1.8 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 33 g.
How is the NKI 12/16 designation read?
The letters mark a machined-ring needle roller bearing with inner ring: 12 mm bore, 16 mm width, 24 mm OD per the series plan. The hardened inner ring is the raceway, so an ordinary k5 shaft seat suffices.
Can the NKI 12/16 run on an unhardened shaft?
Yes — that is the point of this family. The NKI 12/16 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.
How should the NKI 12/16 be mounted?
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.