NJ29-630-ECMA-HB1 bearing: complete specifications & equivalents
The NJ29-630-ECMA-HB1 is a ISO 15 radial bearing sized 630 x 850 x 128 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 630 mm |
| Outer diameter D | 850 mm |
| Width B | 128 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 3300 kN |
| Basic static load rating C0 | 7200 kN |
| Fatigue load limit Pu | 510 kN |
| Reference speed (thermal) | 700 rpm |
| Limiting speed (mechanical) | 900 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 230000 g |
| Manufacturer designation | SKF NJ 29/630 ECMA/HB1 |
| 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 & NJ2900-series range
| Bore d | 24.803 in |
|---|---|
| Outer diameter D | 33.465 in |
| Width B | 5.039 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in NJ2900-series | 340 mm |
| Largest outer diameter in NJ2900-series | 850 mm |
| Width range across NJ2900-series | 72–128 mm |
| Bore position in NJ2900-series (smallest first) | 5 of 5 |
| Bore above smallest NJ2900-series size | 290 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU29-630-ECMA-HB1 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 630×850×128 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 NJ29-630-ECMA-HB1 model number is decoded
SKF NJ 29/630 ECMA/HB1 is a single-row caged cylindrical roller bearing sized 630×850×128 mm — a dimension series 29 (compact OD, normal width), listed in SKF catalogue PUB BU/P1 17000 ch. 6.1. 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 one-piece machined brass cage is reflected in the published speeds and temperature limits. Speed planning for NJ29-630-ECMA-HB1: the catalogue lists 700 r/min thermal reference speed and 900 r/min mechanical limiting speed. The mass entry 230000 g covers the complete catalogue execution. Fit practice for NJ29-630-ECMA-HB1: 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
- mining hoist and winder shafts
- offshore drawworks shafts
- large rolling-mill drive trains
- marine propulsion line 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
- edge loading from shaft deflection beyond the bearing alignment limit (≈ 3-4 minutes of arc for single-row CRB)
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 29 (compact OD, normal width) envelope is shared with the N/NU/NJ/NUP executions of 29/630, but flange configuration and axial-locating behaviour differ — quote the full SKF NJ 29/630 ECMA/HB1 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.
- Catalogue reference and limiting speeds are different criteria: observe the mechanical ceiling even when thermal calculations allow more.
- The 3300/7200 kN ratings are SKF catalogue 17000 (2018) values for the ECMA/HB1 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 NJ29-630-ECMA-HB1?
SKF NJ 29/630 ECMA/HB1 is a single-row caged cylindrical roller bearing with 630 mm bore, 850 mm OD and 128 mm width per ISO 15. SKF lists C 3300 kN, C0 7200 kN, Pu 510 kN, reference speed 700 r/min and limiting speed 900 r/min, mass about 230000 g.
What does the NJ designation and ECMA/HB1 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 NJ29-630-ECMA-HB1 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 NJ29-630-ECMA-HB1 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.