SFK Series
The SFK series is our heavy-load flagship product, combining smaller lead with increased ball circuits at the same shaft diameter. Compared to the SFU series, its dynamic load rating (Ca) is increased by 30%-50%, with significantly enhanced axial rigidity. This series is designed for complete assembly interchangeability with mainstream SFK series products, suitable for heavy-duty cutting machine tools, injection molding machine clamping mechanisms, high-thrust servo pressing, and other heavy-load, high-stiffness applications. Available in C5 and C7 accuracy grades.
Key Features
- Assembly Replacement – Direct replacement of existing same-series assemblies; custom shaft ends per customer drawings
- Ultra-High Load Rating – Multi-circuit (2-4 circuits) design; 30-50% higher dynamic load rating than same-diameter SFU
- Small-Lead Precision – Small lead on large shaft diameter (e.g., Ø32 with 4-5mm lead); high thrust & fine resolution
- Enhanced Rigidity – Enlarged nut OD and increased thread turns; stiffness superior to SFU and SFE
- Long-Life Design – Enhanced ball matching and heat treatment for continuous heavy loads & high impact
Full Specifications
© RFU Motion. Specifications subject to change without notice.
For the latest specs, please contact us.
Custom Manufacturing Available
Standard ball screws and linear guides don't always fit your design. Here's what RFU MOTION can customize based on your drawings:
- Shaft end machining — machined precisely to your drawing
- Screw length — cut to your exact requirement
- Preload — light, medium, heavy, or custom value
- Nut type — standard flange, special shape, or non-standard mounting interface
- Rail length — continuous cutting with end finishing (chamfer or grinding)
- Mounting holes — special thread sizes, hole spacing, or countersunk dimensions
Send us your drawing or specs — we'll deliver exactly what you need.
📦 MOQ: 1 piece / 1 set
⏱️ Lead time: Standard custom 5-7 days | Complex custom 7-15 days | Wire cutting +2 days
Request Custom Quote →