PNA12-28 bearing: complete specifications & equivalents
The PNA12-28 is a DIN 616 radial bearing sized 12 x 28 x 12 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 12 mm |
| Outer diameter D | 28 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | none |
| Basic dynamic load rating C | 7.37 kN |
| Basic static load rating C0 | 9.15 kN |
| Fatigue load limit Pu | 1.08 kN |
| Reference speed (thermal) | 24000 rpm |
| Limiting speed (mechanical) | 28000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 37 g |
| Manufacturer designation | PNA 12/28 |
| 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 | 0.472 in |
|---|---|
| Outer diameter D | 1.102 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 8 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) | 1 of 9 |
| Bore above smallest PNA-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the PNA12-28 model number is decoded
The self-aligning needle roller bearings with inner ring execution PNA 12/28 pairs a flanged needle roller ring (12 mm inner-ring 28 mm OD, 12 mm wide) with a sphered seat: the outer ring swivels a few degrees to follow frame deflection. In SKF nomenclature the P in PNA flags the pivoting, sphered outer ring; dimensions 12×28×12 mm follow the heavy-section plan, and the inner-ring inner ring decision is fixed by the family letter. 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. Speed planning separates the two ceilings: 24,000 r/min thermal reference and 28,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 12 mm seat. Retain the ring axially with washers spanning the full outside surface; point clamps that dig into the sphered surface flatten it and spoil the alignment travel.
Typical equipment & failure modes
Common applications
- pivot bearings where housing bores cannot be kept coaxial
- linkage eyes and clevis mounts on frames that flex
- agricultural machinery joints exposed to frame distortion
- door and gate hinges with heavy radial load
Known failure patterns
- needle edge loading and raceway denting when the shaft deflects beyond the compensation range
- cage pocket wear and roller skew after sustained operation with too little radial preload
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- electrical erosion on VFD-driven shafts without brush or insulated mounting
Selection pitfalls — read before you substitute
- On a 12 mm seat the housing bore quality dominates life: a bore 0.02 mm out of round pinches the 28 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 24,000 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 12 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 7.37/9.15 kN ratings and 37 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 12/28 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 12 mm k5 seat. Both add the sphered outer ring for seat misalignment.
What mounting mistakes ruin a PNA 12/28?
Press on the ring faces only with a fitting sleeve, keep everything square to the 12 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 12/28 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 12/28 have?
A PNA 12/28 measures 12 mm bore/Fw × 28 mm outside diameter × 12 mm width (0.472 × 1.102 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 7.37 kN, static C0 9.15 kN, fatigue limit Pu 1.08 kN, limiting speed 28,000 r/min, reference speed 24,000 r/min, mass about 37 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.