NN3028K bearing: complete specifications & equivalents
The NN3028K is a ISO 15 radial bearing sized 140 x 210 x 53 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 140 mm |
| Outer diameter D | 210 mm |
| Width B | 53 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 330 kN |
| Basic static load rating C0 | 515 kN |
| Fatigue load limit Pu | 53 kN |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6210 g |
| Manufacturer designation | NTN NN3028K |
| 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 | 5.512 in |
|---|---|
| Outer diameter D | 8.268 in |
| Width B | 2.087 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 35 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) | 21 of 40 |
| Bore above smallest NN3000-series size | 115 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NN3028K | 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 NN3028K model number is decoded
NN3028K is an NTN NN cylindrical roller bearing: two integral ribs on the outer ring and a ribless, separable inner ring — a non-locating bearing that lets the shaft float axially, inside the 140×210×53 mm ISO 15 envelope. Numbering ties NN3028K to its envelope: type code NN, series NN3000, 140 mm bore; the 210×53 mm outline therefore swaps dimensionally with other ISO 15 bearings of the same code, though rib arrangements differ by prefix. The 53 mm width and 35.0 mm section put the NN3000 series in the standard section; wide 22/23 variants at the same bore change OD, width and heat generation and are not drop-in swaps. Thermal planning around the 2,800 r/min grease ceiling should include the cage type (a machined or stamped steel cage per the precision execution) and oil-flow option to 3,300 r/min for continuously high-duty 140 mm positions. Housing and shaft fillets must clear the ring chamfers of NN3028K; an oversized radius locks the ring on its face and tilts the 53 mm-wide seat.
Typical equipment & failure modes
Common applications
- CNC lathe and machining-centre spindle radial sets
- precision rotary-table and dividing-head bearings
- high-speed turbine and turbo-blower rotor supports
- coordinate-measuring and semiconductor-equipment drives
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
- edge loading from shaft deflection beyond the 3–4 arc-minute alignment limit
- rolling-contact fatigue after the catalogue L10 life is exceeded
Selection pitfalls — read before you substitute
- At 140 mm bore, oil-lubricated arrangements toward 3,300 r/min need positive flow and drain design; the 6210 g NN3028K ring stores enough heat that grease-only duty needs a careful relubrication calculation.
- The NN rib arrangement is not interchangeable with another prefix on the same 140 mm seat: double row, ribbed inner ring, separable outer. Swapping NU for NJ changes axial location behaviour even though the 210×53 mm envelope matches.
- Grease limiting speed 2,800 r/min and oil 3,300 r/min are different limits for NN3028K: the first is the cage/lubricant mechanical ceiling, the second assumes real oil flow rather than an oil bath.
- The 53 mm width and abutment faces must be square to the axis; a tilted spacer concentrates load across the roller set and shows as uneven raceway polish on the 140 mm inner ring.
- Open NN3028K units need application-supplied sealing and a defined lubricant schedule; film thickness is the first failure mode for line contact when viscosity drops at the 140 mm contact.
- The 330/515 kN ratings, 53 kN Pu and 6210 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NN3028K (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 NN3028K?
NN3028K is an NTN NN double-row precision cylindrical roller bearing to ISO 15: 140 mm bore, 210 mm OD and 53 mm width (5.512 × 8.268 × 2.087 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 330 kN, C0 515 kN, Pu 53 kN, grease limiting speed 2,800 r/min, oil 3,300 r/min, mass about 6210 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. NN3028K 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. NN3028K is supplied in the standard open execution shown in the table.
What does the K tapered bore mean on a precision NN bearing like NN3028K?
The K suffix denotes a 1:12 tapered bore. NN3028K 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 NN3028 execution of the same envelope mounts on a plain seat.
What speeds and lubrication apply to NN3028K?
NTN rates NN3028K at 2,800 r/min with grease and 3,300 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.