K3X5X9-TN bearing: complete specifications & equivalents
The K3X5X9-TN is a DIN 5402 radial bearing sized 3 x 5 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 3 mm |
| Outer diameter D | 5 mm |
| Width B | 9 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 1.68 kN |
| Basic static load rating C0 | 1.53 kN |
| Fatigue load limit Pu | 0.153 kN |
| Reference speed (thermal) | 40000 rpm |
| Limiting speed (mechanical) | 45000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 0.4 g |
| Manufacturer designation | K 3x5x9 TN |
| Standard | DIN 5402 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies); 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 & K-series range
| Bore d | 0.118 in |
|---|---|
| Outer diameter D | 0.197 in |
| Width B | 0.354 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 1 mm |
| Smallest bore in K-series | 3 mm |
| Largest outer diameter in K-series | 63 mm |
| Width range across K-series | 7–32 mm |
| Bore position in K-series (smallest first) | 1 of 22 |
| Bore above smallest K-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the K3X5X9-TN model number is decoded
SKF catalogue number K 3x5x9 TN denotes a needle roller and cage assembly for a 3 mm shaft seat — the cage spaces the rollers, the machine parts provide both raceways, and the 9 mm width is all the radial room it needs. The designation numbers of K 3x5x9 TN state the three machine-seat dimensions — 3 mm journal, 5 mm bore-side complement diameter, 9 mm width — which is why ordering errors here show up as a sloppy or seized fit, not as a returned box. Because there are no rings, execution differences live in the cage: TN polymer cages reduce friction and noise, while the basic steel cage tolerates higher operating temperatures up to the lubricant limit. Selection arithmetic: C 1.68 kN against C0 1.53 kN gives a C0/C ratio of 0.91, and the 0.153 kN fatigue load limit Pu sets the floor for the adjusted-life calculation at contaminated lubrication. Mounting: grind the 3 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 5 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.
Typical equipment & failure modes
Common applications
- connecting rods of small compressors where radial height is critical
- rocker arm and rocker pin pivots on camshafts
- pump and gearbox idler gears running on hardened pins
- hinge and pivot joints in printing and textile machinery
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after overload events
- 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
- rolling-contact fatigue spalling after the rated L10 life
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- At Fw 3 mm the rolling elements are under two millimetres long — handle the K 3x5x9 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.
- Oscillating pivots fail differently: rocking through a small angle concentrates wear in the same roller positions — inspect those zones, and consider rotating the assembly's clock position at service intervals.
- Contamination, not fatigue, kills most small needle bearings: with raceways this narrow, one hard particle dents a full-width line — seal the housing even when the bearing execution itself is open.
- The 1.68/1.53 kN ratings and 0.4 g mass are SKF catalogue values transcribed from ch. 7.1 of PUB BU/P1 17000 (PDF table page 616); combined-type axial ratings appear in the text above because the structured record carries radial values only.
Frequently asked questions
How should the K 3x5x9 TN be mounted?
Slide the assembly over the ground 3 mm journal with a mounting sleeve, bore the housing to E 5 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded.
What limits the service life of a K 3x5x9 TN?
Beyond the L10 rating, the practical limits are journal/raceway hardness for the 3 mm seat, lubricant condition at the roller ends, and contamination through open ends — the 1.0 mm radial section leaves no reserve once a raceway is dented or ribboned.
What are the dimensions and ratings of the K 3x5x9 TN?
A K 3x5x9 TN measures 3 mm bore/Fw × 5 mm outside diameter × 9 mm width (0.118 × 0.197 × 0.354 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.68 kN, static C0 1.53 kN, fatigue limit Pu 0.153 kN, limiting speed 45,000 r/min, reference speed 40,000 r/min, mass about 0.4 g.
How is the K 3x5x9 TN designation read?
K = needle roller and cage assembly (DIN 5402); the three figures give Fw 3 mm (shaft journal), E 5 mm (complement outside diameter, matched by the housing bore) and B 9 mm width. TN marks the glass fibre reinforced PA66 cage.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 7.1 needle roller and cage assemblies on 2026-09-26. Read our editorial & correction policy.