NU348-MA bearing: complete specifications & equivalents
The NU348-MA is a ISO 15 radial bearing sized 240 x 500 x 95 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 240 mm |
| Outer diameter D | 500 mm |
| Width B | 95 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1450 kN |
| Basic static load rating C0 | 2000 kN |
| Fatigue load limit Pu | 180 kN |
| Reference speed (thermal) | 1300 rpm |
| Limiting speed (mechanical) | 2000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 94500 g |
| Manufacturer designation | SKF NU 348 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 & NU300-series range
| Bore d | 9.449 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 3.74 in |
| ISO bore code | 48 |
| Radial section height (D−d)/2 | 130 mm |
| Smallest bore in NU300-series | 17 mm |
| Largest outer diameter in NU300-series | 620 mm |
| Width range across NU300-series | 14–109 mm |
| Bore position in NU300-series (smallest first) | 31 of 33 |
| Bore above smallest NU300-series size | 223 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ348-MA | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 240×500×95 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 NU348-MA model number is decoded
SKF NU 348 MA is a single-row caged cylindrical roller bearing sized 240×500×95 mm — a dimension series 3 (medium-section ISO 15 envelope), listed in SKF catalogue PUB BU/P1 17000 ch. 6.1. Reading the NU prefix: 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. This makes the execution non-locating: the inner ring assembly can float axially in both directions and the bearing cannot support axial load. Reading the order-string suffix MA: the basic (non-E) MA execution with a machined brass cage, standard for the larger and earlier-design sizes. The radial section height is 130.0 mm and the catalogue mass 94500 g; at 1450 kN dynamic rating this is roughly 6.04 kN of C per millimetre of bore before application factors. Fit practice for NU348-MA: 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. 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
- marine propulsion line shafts
- heavy turbogenerator rotor supports
- mining hoist and winder shafts
- offshore drawworks 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
- 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
- fretting corrosion on a loose rotating shaft seat or in a vibratory stand-still
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 3 (medium-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 348, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 348 MA and do not substitute rib styles without checking the shaft locating scheme.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 95 mm-wide ring and concentrates load.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 500 mm raceway.
- The 1450/2000 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 NU348-MA?
SKF NU 348 MA is a single-row caged cylindrical roller bearing with 240 mm bore, 500 mm OD and 95 mm width per ISO 15. SKF lists C 1450 kN, C0 2000 kN, Pu 180 kN, reference speed 1,300 r/min and limiting speed 2,000 r/min, mass about 94500 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 NU348-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 NU348-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.