Manufactured by CHG Bearing, the NNU 4938 BK/SPW33 is a precision Super-Precision Cylindrical Roller Bearings. Key dimensional parameters include a 190 mm bore diameter, a 260 mm outer diameter, and a 69 mm overall width. This component is designed to meet standard load requirements and ensure consistent operational performance. For comprehensive technical evaluation, please explore the detailed specifications, dimensional data, product images, and CAD drawings provided below. A complete PDF data sheet is also readily available for direct download to support your engineering and procurement needs.
NNU 4938 BK/SPW33 - Super-Precision Cylindrical Roller Bearings
Technical Specifications
| Overview | |
|---|---|
| Part Number | NNU 4938 BK/SPW33 |
| Brand | CHG® |
| Characteristics | |
| Bearing Type | Super-precision Cylindrical Roller Bearing |
| Design Type | Tapered Bore 1:12 |
| Structure (Drawing Reference) | Complete Bearing |
| Number of Rows | 2 |
| Ring Type | None |
| Design | NNU Design |
| Tolerance Class | SP |
| Bearing Material | Bearing Steel |
| Coating | None |
| Sealing | None |
| Lubricant | None |
| Features | Annular Lubrication Groove and Lubrication Holes |
| Number of Flanges – Outer Ring | 3 |
| Number of Ribs – Inner Ring | 0 |
| Dimensions | |
| Bore Diameter (d) | 190 mm |
| Width (B) | 69 mm |
| Outer Diameter (D) | 260 mm |
| Minimum Chamfer Dimension rmin | 2 mm |
| Inner Ring Chamfer | 2 mm |
| Outer Ring Chamfer | 1 mm |
| End-face Height Difference h | 1.1 mm |
| Outer-Ring Land Diameter (L2 / D1) | 236 mm |
| Inner Ring Raceway Diameter F | 212 mm |
| Shaft Shoulder Diameter dₐ, min. | 200 mm |
| Shaft Shoulder Diameter dₐ, max. – NNU Design | 209 mm |
| Housing Shoulder Diameter Dₐ, max. | 250 mm |
| Performance | |
| Basic Dynamic Load Rating C (kN) | 402 kN |
| Basic Static Load Rating C₀ (kN) | 880 kN |
| Limiting Speed – Grease (r/min) | 2800 r/min |
| Limiting Speed – Oil-air (r/min) | 3200 r/min |
| Reference Grease Quantity Gref (cm³) | 85 cm³ |
| Fatigue Load Limit Pᵤ (kN) | 90 kN |
| Axial Static Stiffness – Guideline Value (N/µm) | 5380 N/µm |
| Material | |
| Lubrication Groove Width | 8.3 mm |
| Lubrication Holes (qty × Ø mm) | 3 |
| Weight (kg) | 10.5 kg |
| Radial Internal Clearance | C1 mm |
| Internal Design & Weight | |
| Cage Type | Machined Metal Cage |
| Mounting Dimensions | |
| Lubrication Port Thread / Size Φ1 | 213 |
NNU 4938 BK/SPW33 260 mm 190 mm 69 mm Frequently Asked Questions about NNU 4938 BK/SPW33 Super-Precision Cylindrical Roller Bearings
Find key technical answers regarding dimensions, specifications, and replacement options for this model.
To ensure optimum performance of CHG Bearing NNU 4938 BK/SPW33 Super-Precision Cylindrical Roller Bearings under general rotational loads, our application engineers advise an inner-ring shaft tolerance of m5 or k5 for the 190 mm bore. For the 260 mm outer ring, an H7 or J7 housing bore fit is recommended to eliminate creep while accommodating normal thermal gradient expansion.
Engineered according to international ISO boundary plans, CHG Bearing supplies NNU 4938 BK/SPW33 with a precision bore diameter (d) of 190 mm, an outside diameter (D) of 260 mm, and a nominal ring width (B) of 69 mm. This configuration yields an effective cross-sectional wall thickness of 35.0 mm and an envelope ratio (D/d) of 1.37, delivering compact rigidity for OEM machinery housings.
Sourcing NNU 4938 BK/SPW33 directly from CHG Bearing eliminates intermediate brokerage markups while granting you factory-direct engineering backup, rigorous ISO-certified quality assurance, competitive volume wholesale pricing, and dependable supply chain stability for Super-Precision Cylindrical Roller Bearings.
For international ocean and air freight, CHG Bearing packs NNU 4938 BK/SPW33 with industrial VCI anti-corrosion barrier wrapping, sealed polybags, individual cartons, and fumigated ocean-worthy wooden crates. This multi-layer barrier guarantees rust-free storage for a minimum shelf life of 24 to 36 months.
