FCD Series
Ball Screws — Double Nut
Premium double-nut ball screw with spacer preload for zero backlash. C2/C3 ground precision with internal ball return, delivering rigid and repeatable positioning for demanding CNC applications.
FCD Series / Ball Screws — Double Nut
The FCD Series is Luoyang Songju's premium double-nut ball screw, featuring a spacer preload system that achieves zero backlash while maintaining smooth rotation and high efficiency. Two nuts are mounted in opposition with a precision-ground spacer between them, applying a contground preload that eliminates axial play without the torque variation inherent in spring-preloaded designs. This rigid preload method ensures consistent positioning accuracy throughout the screw's service life.
Ground to C2 or C3 accuracy grades with internal ball return circuits, the FCD Series provides exceptional repeatability for CNC machine tool axis drives. Available in diameters from 16mm to 80mm with leads ranging from 5mm to 40mm, FCD ball screws are engineered for the most demanding positioning applications. The internal ball return design keeps the nut body compact while the double-nut configuration provides higher load capacity and rigidity than single-nut alternatives. Ideal for CNC lathe and machining center axis drives, grinding machine feed axes, and precision assembly automation.
Download Drawing Get a QuoteDetailed Parameters
| Series | FCD (Double Nut with Spacer Preload) |
| Nut Type | Double nut, spacer preload |
| Ball Return | Internal recirculation circuit |
| Accuracy Grades | C2, C3 (ground) |
| Preload | Spacer preload — zero backlash |
| Screw Diameter | 16mm, 20mm, 25mm, 32mm, 40mm, 50mm, 63mm, 80mm |
| Lead Range | 5mm, 10mm, 16mm, 20mm, 25mm, 32mm, 40mm |
| Screw Material | Gcr15 bearing steel, induction hardened |
| Screw Hardness | 58–62 HRC (raceway) |
| Nut Material | Gcr15 bearing steel |
| Rigidity | High — double nut configuration |
| Axial Clearance | Zero (preloaded) |
| Max DN Value | 130,000 |
| Max Screw Length | 6000mm (single piece) |
| Operating Temperature | -20°C to +80°C |
| Lubrication | Grease nipple (standard) |
| Seal Type | Double-lip wiper seals |
| Mounting | Standard end machining per DIN 69051 |
| Application | CNC Machine Tool Axis Drives, Grinding Machines, Precision Assembly |
Available Options & Customizations
- Custom end machining
- Ceramic ball variant
- Wipe seal upgrade
- Integrated rotary encoder mount
- Custom lead accuracy
Why Choose FCD Series Ball Screws
The FCD Series combines zero-backlash double-nut preload with ground precision for applications where positioning accuracy, rigidity, and long service life are non-negotiable.
Zero Backlash
Spacer preload system eliminates axial clearance completely, providing consistent bidirectional positioning without torque variation across the full stroke length.
Double Nut Rigidity
Two nuts in opposition double the load-carrying ball contact points, delivering significantly higher axial and radial rigidity than single-nut ball screws.
Ground Precision
C2 or C3 ground accuracy grades ensure exceptional lead accuracy and repeatability, meeting the exacting positioning requirements of high-end CNC machine tools.
Internal Ball Return
Integrated ball recirculation paths keep the nut body diameter compact, enabling installation in space-constrained machine designs without sacrificing performance.
High Load Capacity
Double-nut architecture distributes axial forces across two independent ball circuits, substantially increasing dynamic and static load ratings over single-nut equivalents.
Long Service Life
Precision-ground raceways, contground preload, and effective sealing combine to deliver exceptional durability in continuous-production CNC environments.
Need Zero-Backlash Ball Screws?
Tell us your stroke length, load requirements, accuracy grade, and mounting configuration. Our application engineers will specify the optimal FCD Series ball screw with full technical documentation and competitive pricing. 24-hour response guaranteed.