K4X7X7-TN bearing: complete specifications & equivalents
The K4X7X7-TN is a DIN 5402 radial bearing sized 4 x 7 x 7 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 4 mm |
| Outer diameter D | 7 mm |
| Width B | 7 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 1.72 kN |
| Basic static load rating C0 | 1.32 kN |
| Fatigue load limit Pu | 0.137 kN |
| Reference speed (thermal) | 36000 rpm |
| Limiting speed (mechanical) | 43000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 0.5 g |
| Manufacturer designation | K 4x7x7 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 | 0.157 in |
|---|---|
| Outer diameter D | 0.276 in |
| Width B | 0.276 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 1.5 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) | 2 of 22 |
| Bore above smallest K-series size | 1 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the K4X7X7-TN model number is decoded
The K assembly K 4x7x7 TN is the lowest-radial-section rolling bearing available for a 4 mm shaft: only the 7 mm wide cage-and-roller set sits between journal and bore, giving extreme compactness where even a drawn cup is too heavy a section. Reading the designation: K marks the needle roller and cage assembly, the three numbers give Fw 4 (shaft journal), E 7 (assembly outside diameter) and B 7 (width) in millimetres — the machine parts complete the bearing. 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. Speed planning separates the two ceilings: 36,000 r/min thermal reference and 43,000 r/min mechanical limiting — needle bearings tolerate high rpm only with adequate lubricant film at the 4 mm seat. The assembly is drawn on over a mounting sleeve that spreads the load around all rollers; never drive it home against the cage face, and retain it with a washer whose OD spans the cage, not the rollers.
Typical equipment & failure modes
Common applications
- 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
- universal joint crosses on commercial vehicles
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
- false brinelling of standby equipment under external vibration
- smearing of rollers and journal during idle periods because the radial section holds too little lubricant
Selection pitfalls — read before you substitute
- At Fw 4 mm the rolling elements are under two millimetres long — handle the K 4x7x7 TN like a watch part: one dropped assembly, one over-pressed cup or one coarse journal finish outweighs any catalogue rating difference.
- 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.
- Do not interchange envelope-identical needle families blindly: K 4x7x7 TN shares its 4×7×7 mm outline with inner-ring and sealed siblings whose ratings differ — the family letters are part of the specification, not decoration.
- The 1.72/1.32 kN ratings and 0.5 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
What mounting mistakes ruin a K 4x7x7 TN?
Slide the assembly over the ground 4 mm journal with a mounting sleeve, bore the housing to E 7 mm, and retain with a washer spanning the cage. Never press against the cage or rotate before the bearing is lubricated and loaded.
Is the K 4x7x7 TN 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 K 4x7x7 TN have?
A K 4x7x7 TN measures 4 mm bore/Fw × 7 mm outside diameter × 7 mm width (0.157 × 0.276 × 0.276 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 1.72 kN, static C0 1.32 kN, fatigue limit Pu 0.137 kN, limiting speed 43,000 r/min, reference speed 36,000 r/min, mass about 0.5 g.
What does K 4x7x7 TN mean in SKF part numbering?
K = needle roller and cage assembly (DIN 5402); the three figures give Fw 4 mm (shaft journal), E 7 mm (complement outside diameter, matched by the housing bore) and B 7 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.