NN3056K bearing: complete specifications & equivalents
The NN3056K is a ISO 15 radial bearing sized 280 x 420 x 106 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 280 mm |
| Outer diameter D | 420 mm |
| Width B | 106 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1200 kN |
| Basic static load rating C0 | 2080 kN |
| Fatigue load limit Pu | 174 kN |
| Limiting speed (mechanical) | 1300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 49300 g |
| Manufacturer designation | NTN NN3056K |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & NN3000-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 4.173 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in NN3000-series | 25 mm |
| Largest outer diameter in NN3000-series | 680 mm |
| Width range across NN3000-series | 16–163 mm |
| Bore position in NN3000-series (smallest first) | 31 of 40 |
| Bore above smallest NN3000-series size | 255 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN3056K | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
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 NN3056K model number is decoded
NTN lists NN3056K on the 280×420 mm envelope, 106 mm wide: a line-contact radial bearing with a machined or stamped steel cage per the precision execution and a grease limiting speed of 1,300 r/min. Reading the code: NN for the double-row precision type, then the ISO 15 diameter/width series and the bore code — ×5 = 280 mm (00–03 use the 10/12/15/17 exception table). The roller-set pitch sits inside the 70.0 mm radial section between the 280 mm bore and 420 mm OD; NTN prints Fw/Ew raceway diameters only for selected executions. Equivalent-load planning treats NN3056K as a pure radial bearing: keep P below 1200 kN at the required L10, and let a paired angular-contact or thrust part carry any sustained axial component. Heat the inner ring to max 120 °C for the 280 mm interference fit and support the ring face square during fitting; cocking over a keyway brinells the raceway before first rotation.
Typical equipment & failure modes
Common applications
- high-rpm motorised grinding and milling spindles
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
- high-speed turbine and turbo-blower rotor supports
Known failure patterns
- roller smearing (microwelding) at start-up before the oil film builds under insufficient radial load
- pressed-steel cage pocket wear when rollers skid at light load or too-thin lubricant
- roller-end and raceway scoring from inadequate oil flow under heavy radial load
- electrical pitting on VFD-driven motor shafts without grounding protection
- fretting corrosion on a loose rotating shaft seat
Selection pitfalls — read before you substitute
- At 280 mm bore, oil-lubricated arrangements toward 1,600 r/min need positive flow and drain design; the 49300 g NN3056K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The K tapered bore of NN3056K is driven up to a measured clearance: skipping the drive-up procedure in favour of a normal press fit leaves the precision spindle set either preloaded hot or loose under load.
- Never press either ring through the roller complement when fitting: mounting force goes through the ring faces, or the 420 mm race brinells and releases as vibration within hours.
- The EA high-capacity roller complement changes the load figure versus the basic execution of the same number; the 1200/2080 kN pair here belongs to NN3056K as printed, not to the bare size.
- The NN rib arrangement is not interchangeable with another prefix on the same 280 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 420×106 mm envelope matches.
- The 1200/2080 kN ratings, 174 kN Pu and 49300 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3056K (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.
Frequently asked questions
What are the dimensions and catalogue data of NN3056K?
NN3056K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 280 mm bore, 420 mm OD and 106 mm width (11.024 × 16.535 × 4.173 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 1200 kN, C0 2080 kN, Pu 174 kN, grease limiting speed 1,300 r/min, oil 1,600 r/min, mass about 49300 g. It is open, with a machined or stamped steel cage per the precision execution.
What is the difference between NU, NJ, NUP, N and NF cylindrical roller bearings?
NN and NNU are double-row precision designs rather than single-row rib variants: NN has a ribbed inner ring and separable outer ring, NNU the reverse; both give high radial stiffness for spindles and are commonly ordered with P5/P4 precision and a K 1:12 tapered bore for preload setting. NN3056K is the NN execution.
What do the EA, E and ＊ suffixes mean on NTN cylindrical roller bearings?
EA is NTN's high-capacity design with a pressed sheet-steel cage and optimised roller complement in the same ISO 15 envelope; E marks the high-capacity design at the larger bores; the ＊ symbol printed before the code in the NTN catalogue marks the ULTAGE new-generation specification and is not typed as part of the order number. NN3056K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3056K?
The K suffix denotes a 1:12 tapered bore. NN3056K mounts on a tapered shaft seat or adapter sleeve and is driven up to a measured residual clearance or preload — this is how precision spindle bearings achieve stiffness without locknut guesswork; the cylindrical-bore NN3056 execution of the same envelope mounts on a plain seat.
What speeds and lubrication apply to NN3056K?
NTN rates NN3056K at 1,300 r/min with grease and 1,600 r/min with oil. The grease figure is the cage/film mechanical ceiling; the oil figure assumes circulating or carefully supplied oil that removes heat from the line-contact zone.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.