Recirculating Ball Nut for Ball Screw Assembly and Replacement
DLY recirculating ball nut is designed to work with ball screw shafts for smooth linear motion, low friction transmission and stable repeat positioning. It is widely used as a replacement nut, spare part or assembly component in CNC machines, automation equipment and linear motion systems.
What Is a Recirculating Ball Nut?
A recirculating ball nut is the moving nut component used together with a ball screw shaft. Inside the nut, steel balls roll between the screw groove and the nut raceway. After reaching the end of one rolling path, the balls return through an internal or external circulation path and continue rolling in a closed loop.
This rolling structure helps reduce sliding friction and supports smoother linear movement than ordinary sliding screw nuts. For buyers, the key point is not only the nut name, but whether the nut matches the screw shaft diameter, lead, thread direction, flange size and installation position.
When Should You Buy the Ball Nut Separately?
Many buyers do not always need a complete ball screw assembly. In repair, maintenance and spare parts stocking, buying the ball nut separately can be more practical when the screw shaft is still in good condition.
Replacement and Maintenance
When the original nut has obvious clearance, abnormal noise, poor smoothness or worn ball return parts, a replacement ball nut may help restore motion performance.
Spare Parts Stocking
Distributors and repair service companies often keep common ball nut models in stock for faster replacement and repeat customer orders.
Machine Assembly
OEM buyers may purchase ball nuts separately for batch assembly when screw shafts, support units or machined ends are prepared through different production steps.
Available Recirculating Ball Nut Types
Different ball screw systems use different nut structures. The correct choice depends on mounting space, load, rigidity, speed and whether the buyer needs a standard replacement or a matched ball screw assembly.
| Ball Nut Type | Typical Feature | Suitable Use |
|---|---|---|
| SFU / SFNU Flange Ball Nut | Common flange mounting structure, easy to install and replace. | CNC machines, automation equipment and general linear motion systems. |
| SFE / SFS / SFA Series Nut | Different flange or circulation designs for specific assembly requirements. | Compact equipment, customized modules and replacement parts. |
| DFU Double Nut | Higher rigidity and reduced axial clearance compared with a single nut. | Applications requiring better positioning stability and preload control. |
| Round Ball Nut | Simple cylindrical structure, suitable for limited installation space. | Special fixtures, compact mechanisms and customized machine designs. |
| Left-hand Ball Nut | Matched with left-hand ball screw shaft. | Special transmission designs requiring opposite motion direction. |
Key Parameters to Confirm Before Ordering
A recirculating ball nut is a precision matching component. Before quotation, DLY recommends confirming the following details to avoid mismatch with the existing screw shaft or machine structure.
| Parameter | Why It Matters | Example |
|---|---|---|
| Nominal Diameter | Must match the ball screw shaft diameter. | 12mm, 16mm, 20mm, 25mm, 32mm |
| Lead | Determines the linear travel distance per screw rotation. | 4mm, 5mm, 10mm, 20mm |
| Nut Type | Affects flange size, mounting method and machine compatibility. | SFU, SFS, SFE, SFA, DFU |
| Mounting Dimensions | Must fit the existing bracket, flange seat or mounting plate. | Flange OD, PCD, hole diameter |
| Thread Direction | Right-hand and left-hand ball screws require different matching nuts. | Right-hand or left-hand |
How to Identify the Correct Replacement Ball Nut
If you are replacing an old ball nut, the model name alone may not always be enough. Some machines use customized ball nuts or special mounting dimensions. The following information helps DLY check the replacement faster.
Existing Model Marking
Send the model printed or engraved on the old nut, such as SFU1605, SFU2005 or DFU2505.
Screw Shaft Size
Confirm the screw diameter and lead. If unsure, measure how far the nut moves when the screw turns one full rotation.
Mounting Dimensions
Measure flange diameter, nut body diameter, total length, mounting hole spacing and hole quantity.
Photos or Drawings
Clear photos from the front, side and mounting surface can help us identify the nut type faster.
Applications of Recirculating Ball Nuts
CNC Machines
Used for axis feed movement, repair and replacement of worn ball screw nuts.
Automation Modules
Used in compact linear actuators, positioning units and automatic feeding systems.
Machine Repair
Suitable for replacing ball nuts in woodworking machines, engraving machines and light industrial equipment.
Distributor Stock
Common ball nut models can be stocked for spare parts supply and repeat customer orders.
Why Choose DLY Recirculating Ball Nuts?
- DLY supplies common ball nut models for ball screw replacement and assembly.
- Support for separate ball nut orders and complete ball screw with nut assemblies.
- Model checking based on nut marking, screw size, mounting dimensions, photos or drawings.
- Suitable for overseas distributors, OEM buyers, machine builders and repair service companies.
- Factory-direct communication by email and WhatsApp for faster quotation confirmation.
FAQ About Recirculating Ball Nuts
Q1: Can I buy only the ball nut without the screw shaft?
Yes. DLY can supply ball nuts separately. However, the nut must match the screw shaft diameter, lead, thread direction and circulation structure.
Q2: How do I know whether my old screw shaft can still be used?
Check whether the screw raceway is smooth and free from rust, scratches, dents or serious wear. If the shaft is damaged, replacing only the nut may not restore smooth running.
Q3: What information should I send for quotation?
Please send the ball nut model, screw diameter, lead, nut type, quantity and photos or drawings. If you need a matched screw shaft, also provide the required length and end machining drawing.
Q4: Can DLY supply a complete ball screw and nut assembly?
Yes. Besides separate recirculating ball nuts, DLY can supply complete ball screw assemblies with matched nuts and customized end machining.
Q5: Are recirculating ball nuts suitable for distributor stock?
Yes. Common models are suitable for spare parts stock, machine repair and repeat orders. Distributors can contact DLY for common model recommendations.
Get Recirculating Ball Nut Price from DLY
Send us your ball nut model, screw diameter, lead, mounting dimensions, photos or drawings. DLY will help check whether you need only a replacement ball nut or a complete ball screw and nut assembly.
Email: export@dlybearing.com
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