NU406-MA bearing: complete specifications & equivalents
The NU406-MA is a ISO 15 radial bearing sized 30 x 90 x 23 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 30 mm |
| Outer diameter D | 90 mm |
| Width B | 23 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 60.5 kN |
| Basic static load rating C0 | 53 kN |
| Fatigue load limit Pu | 6.8 kN |
| Reference speed (thermal) | 9000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 750 g |
| Manufacturer designation | SKF NU 406 MA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings); 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 & NU400-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 0.906 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in NU400-series | 25 mm |
| Largest outer diameter in NU400-series | 310 mm |
| Width range across NU400-series | 21–72 mm |
| Bore position in NU400-series (smallest first) | 2 of 17 |
| Bore above smallest NU400-series size | 5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU406 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×90×23 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| NJ406-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 30×90×23 mm and equivalent catalogue ratings; the NJ execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
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 NU406-MA model number is decoded
For a 30 mm shaft, SKF lists NU406-MA as single-row caged cylindrical roller: 90 mm OD, 23 mm wide, Pu 6.8 kN, the catalogue lists 9,000 r/min thermal reference speed and 11,000 r/min mechanical limiting speed. The NU configuration means two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable; functionally the bearing is non-locating: the inner ring assembly can float axially in both directions and the bearing cannot support axial load. The MA suffix marks the basic (non-E) execution with a machined brass cage, the standard choice for the larger and earlier-design sizes. The one-piece machined brass cage is reflected in the published speeds and temperature limits. With C 60.5 kN and C0 53 kN, size the bearing on the 30×90 mm ISO 15 envelope and check the 6.8 kN Pu against the equivalent-load floor; the catalogue lists 9,000 r/min thermal reference speed and 11,000 r/min mechanical limiting speed. Mounting: fit the inner ring and roller assembly onto the shaft and the outer ring into the housing independently; thermal expansion is absorbed by axial float, so do not trap the inner ring between shaft shoulders. A 30 mm seat normally takes a k5 interference with an H7 housing bore when the inner ring rotates.
Typical equipment & failure modes
Common applications
- compressor crank and rotor shafts
- machine-tool radial spindle supports
- conveyor drive-pulley shafts
- medium industrial gearbox shafts
Known failure patterns
- inner-ring raceway spalling from overload or contamination in the line-contact hertz zone
- outer-ring raceway fatigue after extended service at loads above the catalogue L10 rating
- cage pocket wear from roller skew at light load
- cage pocket wear from roller skidding at insufficient radial load or during start-up before oil film build-up
- roller-end scoring from inadequate oil flow in the roller-raceway contact
- edge-loading fatigue after shaft deflection beyond the 3–4 minute alignment limit
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Do not use a NU bearing where axial load must be carried — the design carries radial load only
- The dimension series 4 (heavy-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 406, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 406 MA and do not substitute rib styles without checking the shaft locating scheme.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 90 mm raceway.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 23 mm-wide ring and concentrates load.
- The 60.5/53 kN ratings are SKF catalogue 17000 (2018) values for the MA execution; re-verify against the current catalogue for critical drives and keep the catalogue version with the specification.
Frequently asked questions
What are the dimensions and catalogue data of NU406-MA?
SKF NU 406 MA is a single-row caged cylindrical roller bearing with 30 mm bore, 90 mm OD and 23 mm width per ISO 15. SKF lists C 60.5 kN, C0 53 kN, Pu 6.8 kN, reference speed 9,000 r/min and limiting speed 11,000 r/min, mass about 750 g.
What does the NU designation and MA suffix mean?
The MA suffix marks the basic (non-E) execution with a machined brass cage, the standard choice for the larger and earlier-design sizes. Structurally this execution has two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable.
Can NU406-MA take axial load and locate the shaft?
No — the inner ring has no flanges, so the NU bearing is non-locating and carries radial load only; use NJ (one direction), NUP (both directions) or a paired thrust bearing for axial duty.
How does NU406-MA compare with the other executions in the same envelope?
The N/NU/NJ/NUP executions share the ISO 15 envelope and load ratings but differ in flange arrangement and axial-locating behaviour; quote the exact order number.
What limits the service life of this bearing most often?
Line-contact fatigue above the L10 rating, cage wear at light loads and high temperatures, and edge loading from misalignment beyond about 3–4 minutes of arc are the typical failure drivers.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings on 2026-09-26. Read our editorial & correction policy.