NK16-20 bearing: complete specifications & equivalents
The NK16-20 is a DIN 616 radial bearing sized 16 x 24 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 16 mm |
| Outer diameter D | 24 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 14.5 kN |
| Basic static load rating C0 | 20 kN |
| Fatigue load limit Pu | 2.4 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 28 g |
| Manufacturer designation | NK 16/20 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without 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. 7.3 machined rings with flanges, without 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 & NK-series range
| Bore d | 0.63 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 4 mm |
| Smallest bore in NK-series | 5 mm |
| Largest outer diameter in NK-series | 130 mm |
| Width range across NK-series | 10–40 mm |
| Bore position in NK-series (smallest first) | 10 of 46 |
| Bore above smallest NK-series size | 11 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NK16-20 model number is decoded
NK 16/20 belongs to the machined-ring needle roller family: an outer ring turned and ground to 24 mm with two retaining flanges, a roller-and-cage set inside, and envelope 16×24×20 mm on a hardened 16 mm shaft. The NK 16/20 code states Fw 16 and width 20 mm directly; because the family has no inner ring, the 16 mm journal must be ground, hardened to 58–64 HRC and finished to the raceway tolerance the catalogue specifies. The machined ring is through-hardened and ground on OD, bore-side raceway and faces; the flanged lip design means the housing shoulder can be omitted — the ring clamps axially between housing wall and cover washer. The 28 g catalogue mass and 4.0 mm radial section ((24−16)/2) frame a rating of about 0.91 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Fit the outer ring with a press and a fitting sleeve, not by hammering the flanges — rolled flanges chip; the 24 mm ground OD takes the press fit that prevents outer-ring creep in oscillating duty.
Typical equipment & failure modes
Common applications
- piston-pin style pivots in hydraulic pumps
- guide rollers running on hardened tracks
- swing arms and lever pivots with oscillating duty
- cam followers built up from separate components
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
- false brinelling of standby equipment under external vibration
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- On a 16 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.
- 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 14.5/20 kN ratings and 28 g mass are SKF catalogue values transcribed from ch. 7.3 of PUB BU/P1 17000 (PDF table page 626); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
What limits the service life of a NK 16/20?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 16 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 4.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the NK 16/20?
A NK 16/20 measures 16 mm bore/Fw × 24 mm outside diameter × 20 mm width (0.63 × 0.945 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 14.5 kN, static C0 20 kN, fatigue limit Pu 2.4 kN, limiting speed 26,000 r/min, reference speed 22,000 r/min, mass about 28 g.
How is the NK 16/20 designation read?
NK names a machined-ring needle roller bearing without inner ring: the figures give Fw 16 mm and width 20 mm, OD 24 mm comes from the dimension series, and the flanged outer ring retains the caged rollers.
Can the NK 16/20 run on an unhardened shaft?
No. In this execution the 16 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.3 machined rings with flanges, without an inner ring on 2026-09-26. Read our editorial & correction policy.