NUP3984-ECMA bearing: complete specifications & equivalents
The NUP3984-ECMA is a ISO 15 radial bearing sized 420 x 560 x 106 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 420 mm |
| Outer diameter D | 560 mm |
| Width B | 106 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1680 kN |
| Basic static load rating C0 | 3650 kN |
| Fatigue load limit Pu | 310 kN |
| Reference speed (thermal) | 950 rpm |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 79500 g |
| Manufacturer designation | SKF NUP 3984 ECMA |
| 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 & NUP3900-series range
| Bore d | 16.535 in |
|---|---|
| Outer diameter D | 22.047 in |
| Width B | 4.173 in |
| ISO bore code | 84 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in NUP3900-series | 420 mm |
| Largest outer diameter in NUP3900-series | 620 mm |
| Width range across NUP3900-series | 106–118 mm |
| Bore position in NUP3900-series (smallest first) | 1 of 2 |
| Bore above smallest NUP3900-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NUP3984-ECMA model number is decoded
For a 420 mm shaft, SKF lists NUP3984-ECMA as single-row caged cylindrical roller: 560 mm OD, 106 mm wide, Pu 310 kN, the catalogue lists 950 r/min thermal reference speed and 1,500 r/min mechanical limiting speed. The NUP configuration means two integral flanges on the outer ring plus one integral flange and one loose flange ring on the inner ring; functionally the bearing is a locating bearing that positions the shaft axially in both directions while keeping the cylindrical-roller radial capacity. The ECMA suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Load-per-bore for the 420 mm seat is about 4.00 kN/mm, typical of dimension series 39 (compact OD); use C0 3650 kN for static checks such as crane hook blocks standing under load. Mounting: the loose inner-ring flange must be fitted on the correct side and retained by the shaft abutment; never omit it during reassembly or the bearing loses its two-direction locating function. A 420 mm seat normally takes a m6 interference with an H6 housing bore when the inner ring rotates.
Typical equipment & failure modes
Common applications
- offshore drawworks shafts
- large rolling-mill drive trains
- marine propulsion line shafts
- heavy turbogenerator rotor supports
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
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Do not use a NUP bearing where a floating non-locating bearing is required — the loose inner flange makes it a locating bearing
- The dimension series 39 (compact OD) envelope is shared with the N/NU/NJ/NUP executions of 3984, but flange configuration and axial-locating behaviour differ — quote the full SKF NUP 3984 ECMA 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 560 mm raceway.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 560 mm raceway.
- The 1680/3650 kN ratings are SKF catalogue 17000 (2018) values for the ECMA 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 NUP3984-ECMA?
SKF NUP 3984 ECMA is a single-row caged cylindrical roller bearing with 420 mm bore, 560 mm OD and 106 mm width per ISO 15. SKF lists C 1680 kN, C0 3650 kN, Pu 310 kN, reference speed 950 r/min and limiting speed 1,500 r/min, mass about 79500 g.
What does the NUP designation and ECMA suffix mean?
The ECMA 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 outer ring plus one integral flange and one loose flange ring on the inner ring.
Can NUP3984-ECMA take axial load and locate the shaft?
Yes, in both directions: the integral inner flange plus the loose flange ring close both axial paths. Do not pair it with another locating bearing without thermal clearance.
How does NUP3984-ECMA 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.