NJ340-ECML bearing: complete specifications & equivalents
The NJ340-ECML is a ISO 15 radial bearing sized 200 x 420 x 80 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 200 mm |
| Outer diameter D | 420 mm |
| Width B | 80 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1230 kN |
| Basic static load rating C0 | 1630 kN |
| Fatigue load limit Pu | 150 kN |
| Reference speed (thermal) | 1400 rpm |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 56500 g |
| Manufacturer designation | SKF NJ 340 ECML |
| 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 & NJ300-series range
| Bore d | 7.874 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 3.15 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in NJ300-series | 17 mm |
| Largest outer diameter in NJ300-series | 500 mm |
| Width range across NJ300-series | 14–95 mm |
| Bore position in NJ300-series (smallest first) | 27 of 29 |
| Bore above smallest NJ300-series size | 183 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU340-ECML | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 200×420×80 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 NJ340-ECML model number is decoded
Ordering number SKF NJ 340 ECML resolves to a 200×420×80 mm single-row caged cylindrical roller bearing (dimension series 3 (medium-section ISO 15 envelope)); two integral flanges on the inner ring and no flanges on the outer ring; the inner ring retains the roller set. 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 ECML suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Selection arithmetic: C0/C ≈ 1.33 (1630 against 1230 kN), and the Pu figure 150 kN is the fatigue load-limit floor for the SKF life equation; the catalogue lists 1,400 r/min thermal reference speed and 2,800 r/min mechanical limiting speed. Fit practice for NJ340-ECML: 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. Single-row cylindrical rollers tolerate only about 3–4 minutes of arc misalignment, so verify shaft and housing alignment.
Typical equipment & failure modes
Common applications
- large rolling-mill drive trains
- marine propulsion line shafts
- heavy turbogenerator rotor supports
- mining hoist and winder 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
- 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
- brinelling from static overload or impact during handling and mounting
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 3 (medium-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 340, but flange configuration and axial-locating behaviour differ — quote the full SKF NJ 340 ECML 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 80 mm-wide ring and concentrates load.
- The 1230/1630 kN ratings are SKF catalogue 17000 (2018) values for the ECML 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 NJ340-ECML?
SKF NJ 340 ECML is a single-row caged cylindrical roller bearing with 200 mm bore, 420 mm OD and 80 mm width per ISO 15. SKF lists C 1230 kN, C0 1630 kN, Pu 150 kN, reference speed 1,400 r/min and limiting speed 2,800 r/min, mass about 56500 g.
What does the NJ designation and ECML suffix mean?
The ECML suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. 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 NJ340-ECML 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 NJ340-ECML 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.