PNA25-47 bearing: complete specifications & equivalents
The PNA25-47 is a DIN 616 radial bearing sized 25 x 47 x 20 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 25 mm |
| Outer diameter D | 47 mm |
| Width B | 20 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 22.9 kN |
| Basic static load rating C0 | 38 kN |
| Fatigue load limit Pu | 4.8 kN |
| Reference speed (thermal) | 13000 rpm |
| Limiting speed (mechanical) | 15000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 160 g |
| Manufacturer designation | PNA 25/47 |
| Standard | DIN 616 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring); 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 & PNA-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.787 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 11 mm |
| Smallest bore in PNA-series | 12 mm |
| Largest outer diameter in PNA-series | 62 mm |
| Width range across PNA-series | 12–20 mm |
| Bore position in PNA-series (smallest first) | 6 of 9 |
| Bore above smallest PNA-series size | 13 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the PNA25-47 model number is decoded
PNA 25/47 combines machined-ring needle roller capacity with self-alignment: 25×47×20 mm envelope, convex outer-ring outside running in a correspondingly sphered washer or housing seat. Reading the designation: PNA marks the self-aligning execution (inner-ring inner ring), the numbers giving 25 mm inner-ring bore and 20 mm width; the sphered outside diameter 47 mm follows the series plan. These are heavy-section machined rings, not drawn cups: the sphered outside surface is ground, the flanges retain the rollers, and the PNA execution adds the ground inner ring for unhardened shafts. The 160 g catalogue mass and 11.0 mm radial section ((47−25)/2) frame a rating of about 0.92 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. The sphered seat must be clean and lightly oiled — a scored seat converts the alignment feature into a friction lock, and the needle rollers then take the seat error the family was meant to absorb.
Typical equipment & failure modes
Common applications
- linkage eyes and clevis mounts on frames that flex
- agricultural machinery joints exposed to frame distortion
- door and gate hinges with heavy radial load
- construction equipment blade and arm pivots
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- polymer cage deformation when the local temperature exceeds the 120 °C sustained limit
- grease starvation at the roller ends when relubrication intervals are stretched in dirty duty
- brinelling of raceways from impact or pressing force transmitted through the rolling elements
Selection pitfalls — read before you substitute
- On a 25 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 47 mm ring or cup into a lobed shape, and the rollers then trace the housing's geometry error, not the design load.
- Reference and limiting speeds are different limits: the 13,000 r/min reference is the thermal criterion under load, The limiting value is mechanical; the reference value is thermal under load, and grease choice moves it substantially.
- Hardness is load capacity: in families without an inner ring the 25 mm journal must hold 58–64 HRC with a ground finish; a surface that looks fine but sits at 45 HRC will rib the raceway within weeks.
- The 22.9/38 kN ratings and 160 g mass are SKF catalogue values transcribed from ch. 7.6 of PUB BU/P1 17000 (PDF table page 652); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
Does the PNA 25/47 need a hardened and ground shaft?
Depends on the family member: RPNA runs directly on the shaft (hardened, 58–64 HRC, ground), while PNA includes a ground inner ring for an ordinary 25 mm k5 seat. Both add the sphered outer ring for seat misalignment.
What mounting mistakes ruin a PNA 25/47?
Press on the ring faces only with a fitting sleeve, keep everything square to the 25 mm seat, and never transmit force through the rolling elements. Follow the catalogue's seat tolerances — the narrow needle contact forgives neither tilt nor burrs.
Is the PNA 25/47 sealed?
No — this execution is open and depends on the housing sealing arrangement; grease it at assembly and keep the relubrication interval short in dirty duty.
Which dimensions does the PNA 25/47 have?
A PNA 25/47 measures 25 mm bore/Fw × 47 mm outside diameter × 20 mm width (0.984 × 1.85 × 0.787 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 22.9 kN, static C0 38 kN, fatigue limit Pu 4.8 kN, limiting speed 15,000 r/min, reference speed 13,000 r/min, mass about 160 g.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.6 alignment needle roller bearings, with an inner ring on 2026-09-26. Read our editorial & correction policy.