K12X18X12-TN bearing: complete specifications & equivalents
The K12X18X12-TN is a DIN 5402 radial bearing sized 12 x 18 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 | 18 mm |
| Width B | 12 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 9.52 kN |
| Basic static load rating C0 | 10 kN |
| Fatigue load limit Pu | 1.18 kN |
| Reference speed (thermal) | 26000 rpm |
| Limiting speed (mechanical) | 30000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 6 g |
| Manufacturer designation | K 12x18x12 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 | 0.472 in |
|---|---|
| Outer diameter D | 0.709 in |
| Width B | 0.472 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 3 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) | 9 of 22 |
| Bore above smallest K-series size | 9 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the K12X18X12-TN model number is decoded
In SKF catalogue PUB BU/P1 17000 ch. 7.1, K 12x18x12 TN appears as a needle roller and cage assembly with complement diameter E 18 mm and width 12 mm — a self-contained roller set that turns a 12 mm shaft and its housing into a complete bearing. K 12×18×12 is a boundary plan, not an envelope: the assembly has no rings, so E 18 mm is the needle set diameter the housing bore must match, and the 12 mm journal must be ground and hardened. 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. The 6 g catalogue mass and 3.0 mm radial section ((18−12)/2) frame a rating of about 0.79 kN dynamic per millimetre of bore — the needle construction's density advantage over ball bearings of the same envelope. Mounting: grind the 12 mm journal to the catalogue raceway tolerance after hardening to 58–64 HRC, bore the housing to E 18 mm H6, and slide the assembly in axially — pressing through the cage distorts it and locks the rollers.
Typical equipment & failure modes
Common applications
- pump and gearbox idler gears running on hardened pins
- hinge and pivot joints in printing and textile machinery
- universal joint crosses on commercial vehicles
- planetary gear pins in compact transmissions
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
- abrasive paste formation from dust ingressing past open ends without effective housing seals
- corrosion pitting from condensation in intermittently operated machinery
- rapid raceway scoring when the shaft journal hardness drops below 58 HRC or the ground finish wears away
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 18 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 26,000 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 9.52/10 kN ratings and 6 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
Does the K 12x18x12 TN need a hardened and ground shaft?
No. In this execution the 12 mm shaft journal is the inner raceway: it must be ground and hardened to 58–64 HRC (with matching housing bore quality on the outside). If the shaft cannot meet that, order the inner-ring sibling (NKI/NA execution) plus its ground inner ring instead.
What mounting mistakes ruin a K 12x18x12 TN?
Slide the assembly over the ground 12 mm journal with a mounting sleeve, bore the housing to E 18 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 12x18x12 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 12x18x12 TN have?
A K 12x18x12 TN measures 12 mm bore/Fw × 18 mm outside diameter × 12 mm width (0.472 × 0.709 × 0.472 in). From SKF catalogue PUB BU/P1 17000: radial dynamic rating C 9.52 kN, static C0 10 kN, fatigue limit Pu 1.18 kN, limiting speed 30,000 r/min, reference speed 26,000 r/min, mass about 6 g.
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.