NJ409 bearing: complete specifications & equivalents
The NJ409 is a ISO 15 radial bearing sized 45 x 120 x 29 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 45 mm |
| Outer diameter D | 120 mm |
| Width B | 29 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 106 kN |
| Basic static load rating C0 | 102 kN |
| Fatigue load limit Pu | 13.4 kN |
| Reference speed (thermal) | 6700 rpm |
| Limiting speed (mechanical) | 7500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1650 g |
| Manufacturer designation | SKF NJ 409 |
| 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 & NJ400-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.142 in |
| ISO bore code | 09 |
| Radial section height (D−d)/2 | 37.5 mm |
| Smallest bore in NJ400-series | 25 mm |
| Largest outer diameter in NJ400-series | 280 mm |
| Width range across NJ400-series | 21–65 mm |
| Bore position in NJ400-series (smallest first) | 5 of 13 |
| Bore above smallest NJ400-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ409-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 45×120×29 mm envelope per ISO 15; catalogue load ratings differ by >10% — re-rate the application before substituting. |
| NU409 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 45×120×29 mm and equivalent catalogue ratings; the NU 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 NJ409 model number is decoded
NJ409 is the 45 mm bore entry in the NJ400 range: a 45×120×29 mm single-row caged cylindrical roller bearing with a pressed sheet-steel window-type cage, rated C 106 kN / C0 102 kN. Structurally, the NJ design has two integral flanges on the inner ring and no flanges on the outer ring; the inner ring retains the roller set. In arrangement terms it is able to locate the shaft axially in one direction; an HJ angle ring on the opposite side converts it into two-direction location. The plain designation (no cage suffix) identifies the basic execution supplied with a standard pressed-steel cage. The pressed sheet-steel window-type cage is reflected in the published speeds and temperature limits. The radial section height is 37.5 mm and the catalogue mass 1650 g; at 106 kN dynamic rating this is roughly 2.36 kN of C per millimetre of bore before application factors. Mounting: orient the inner-ring flange side toward the axial load direction; if an HJ angle ring is used, verify its fit and clearance before locking the arrangement. A 45 mm seat normally takes a k5 interference with an H7 housing bore when the inner ring rotates.
Typical equipment & failure modes
Common applications
- electric-motor shafts in pumps and fans
- compressor crank and rotor shafts
- machine-tool radial spindle supports
- conveyor drive-pulley 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
- polymer cage cracking or softening after sustained running above 120 °C or with incompatible lubricant
- surface distress (micro-pitting) when the EHL film falls below the composite roughness at high specific load
- edge-loading fatigue after shaft deflection beyond the 3–4 minute alignment limit
- smearing (microwelding) on roller surfaces during skid starts with insufficient minimum load
Selection pitfalls — read before you substitute
- Do not use a NJ bearing where two-direction axial location is required without an HJ angle ring
- The dimension series 4 (heavy-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 409, but flange configuration and axial-locating behaviour differ — quote the full SKF NJ 409 and do not substitute rib styles without checking the shaft locating scheme.
- Catalogue reference and limiting speeds are different criteria: observe the mechanical ceiling even when thermal calculations allow more.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 29 mm-wide ring and concentrates load.
- The 106/102 kN ratings are SKF catalogue 17000 (2018) values for the basic 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 NJ409?
SKF NJ 409 is a single-row caged cylindrical roller bearing with 45 mm bore, 120 mm OD and 29 mm width per ISO 15. SKF lists C 106 kN, C0 102 kN, Pu 13.4 kN, reference speed 6,700 r/min and limiting speed 7,500 r/min, mass about 1650 g.
What does the NJ designation and plain suffix mean?
The plain designation (no cage suffix) identifies the basic execution supplied with a standard pressed-steel cage. Structurally this execution has two integral flanges on the inner ring and no flanges on the outer ring; the inner ring retains the roller set.
Can NJ409 take axial load and locate the shaft?
In one direction only, via the two inner-ring flanges. Add an HJ angle ring on the opposite side for two-direction location.
How does NJ409 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.