NSK 1218K dimensions and model data
NSK 1218K is a listed self-aligning ball bearing with a 1:12 tapered bore. Its catalogue boundary dimensions are 90×160×30 mm (nominal bore d × outside diameter D × width B).
Bore construction and mounting
The K suffix on 1218K identifies a 1:12 tapered bore, not a clearance or precision grade. The listed 90 mm bore is a nominal bearing dimension; it is not a specification for a straight shaft or an adapter sleeve bore. Match the mounting arrangement and verify residual internal clearance using the applicable mounting instructions.
Using the model-specific load factors
For radial load Fr greater than zero, first compare Fa/Fr with e = 0.17. Use loads in one consistent unit. When Fa/Fr ≤ 0.17, the catalogue dynamic equivalent load is P = Fr + 3.8Fa. Above that threshold, P = 0.65Fr + 5.8Fa. The static equivalent load is P0 = Fr + 3.9Fa. These are catalogue calculation rules for this bearing family, not a complete application approval.
Selection limits and missing specifications
- Cr = 63 kN and C0r = 23.5 kN are rated calculation values, not interchangeable maximum working loads.
- The listed speed limits are 3600 r/min with grease and 4300 r/min with oil. They are lubrication-qualified references, not a guaranteed machine operating speed.
- This bearing family accommodates angular misalignment through its spherical outer-ring raceway. It is not a high-axial-load substitute for a thrust bearing.
- NSK gives an approximate family-level misalignment range of 4° to 7° under normal loads. Adjacent shoulders, seals and other surrounding parts can reduce the available angle; this is not a model-specific allowable-angle guarantee.
- The mounting table uses da as a minimum, Da as a maximum and ra as a maximum. These are adjacent-part constraints, not alternative bearing dimensions.
- Precision class, internal clearance, cage material and a particular lubricant are not established for this individual designation by the model row. No missing value is treated as zero.
- The mass value is published once for the shared cylindrical/tapered catalogue row. A separate measured mass for the K variant is not supplied here.
Technical basis:NSK Rolling Bearings for Industrial Machinery, E1103d (2025), Part C, C122–C123 and introduction C116; source checked 2026-10-01. Values are independently organised for reference and comparison, not sales or an installation approval.
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