Product Overview
SFU ball screw nut is engineered for demanding linear motion applications where positioning accuracy and load consistency cannot be compromised. Designed to pair directly with SFU-series ball screw shafts, each nut converts rotary input into precise linear displacement through an internal recirculating ball circuit - delivering transmission efficiency above 90% with axial backlash that can be reduced to near zero through preload adjustment.
Manufactured from GCr15 bearing steel (equivalent to SUJ2/52100), ground to surface hardness HRC 58–62, and available in accuracy grades C3 through C10, these nuts are a direct-fit solution for CNC machining centers, semiconductor handling equipment, industrial robots, and precision gantry systems.
We offer standard flange type (SFU), cylindrical type (SFU-R), and double-nut extended type (SFU-D) across nominal diameters from 12 mm to 80 mm with leads from 2 mm to 20 mm.
Specifications - SFU Series Ball Screw Nut
Unit: mm | Load ratings in N
| Model No. | d (mm) | Lead l (mm) | Ball Dia. Da (mm) | D | A | B | L | W | H | X | Q | n | Dynamic Load Ca (N) | Static Load Coa (N) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SFU1204 | 12 | 4 | 2.5 | 24 | 40 | 10 | 40 | 32 | 30 | 4.5 | M6×1 | 1×3 | 451 | 709 |
| SFU1604 | 16 | 4 | 2.381 | 28 | 48 | 10 | 36 | 38 | 40 | 5.5 | M6×1 | 1×3 | 488 | 940 |
| SFU1605 | 16 | 5 | 3.175 | 28 | 48 | 10 | 42 | 38 | 40 | 5.5 | M6×1 | 1×3 | 666 | 1143 |
| SFU1605-4 | 16 | 5 | 3.175 | 28 | 48 | 10 | 50 | 38 | 40 | 5.5 | M6×1 | 1×4 | 888 | 1525 |
| SFU1610 | 16 | 10 | 3.175 | 28 | 48 | 10 | 57 | 38 | 40 | 5.5 | M6×1 | 1×3 | 716 | 1232 |
| SFU2004 | 20 | 4 | 2.381 | 36 | 58 | 10 | 42 | 47 | 44 | 6.6 | M6×1 | 1×3 | 541 | 1187 |
| SFU2005 | 20 | 5 | 3.175 | 36 | 58 | 10 | 42 | 47 | 44 | 6.6 | M6×1 | 1×3 | 749 | 1495 |
| SFU2005-4 | 20 | 5 | 3.175 | 36 | 58 | 10 | 51 | 47 | 44 | 6.6 | M6×1 | 1×4 | 999 | 1994 |
| SFU2504 | 25 | 4 | 2.381 | 40 | 62 | 10 | 42 | 51 | 48 | 6.6 | M6×1 | 1×3 | 605 | 1534 |
| SFU2505 | 25 | 5 | 3.175 | 40 | 62 | 10 | 42 | 51 | 48 | 6.6 | M6×1 | 1×3 | 839 | 1935 |
| SFU2505-4 | 25 | 5 | 3.175 | 40 | 62 | 10 | 51 | 51 | 48 | 6.6 | M6×1 | 1×4 | 1119 | 2581 |
| SFU2510 | 25 | 10 | 4.762 | 40 | 62 | 10 | 70 | 51 | 48 | 6.6 | M6×1 | 1×3 | 1427 | 2771 |
| SFU2510-4 | 25 | 10 | 4.762 | 40 | 62 | 12 | 85 | 51 | 48 | 6.6 | M6×1 | 1×4 | 1903 | 3695 |
| SFU3205-4 | 32 | 5 | 3.175 | 50 | 80 | 12 | 52 | 65 | 62 | 9 | M6×1 | 1×4 | 1264 | 3402 |
| SFU3210 | 32 | 10 | 6.35 | 50 | 80 | 12 | 74 | 65 | 62 | 9 | M6×1 | 1×3 | 2319 | 4575 |
| SFU3210-4 | 32 | 10 | 6.35 | 50 | 80 | 12 | 90 | 65 | 62 | 9 | M6×1 | 1×4 | 3092 | 6101 |
| SFU4005-4 | 40 | 5 | 3.175 | 63 | 93 | 14 | 55 | 78 | 70 | 9 | M8×1 | 1×4 | 1407 | 4341 |
| SFU4010 | 40 | 10 | 6.35 | 63 | 93 | 14 | 71 | 78 | 70 | 9 | M8×1 | 1×3 | 2610 | 5834 |
| SFU4010-4 | 40 | 10 | 6.35 | 63 | 93 | 14 | 93 | 78 | 70 | 9 | M8×1 | 1×4 | 3480 | 7779 |
| SFU5010-4 | 50 | 10 | 6.35 | 75 | 110 | 16 | 93 | 93 | 85 | 11 | M8×1 | 1×4 | 3898 | 10325 |
| SFU6310-4 | 63 | 10 | 6.35 | 90 | 125 | 18 | 98 | 108 | 95 | 11 | M8×1 | 1×4 | 4401 | 13611 |
| SFU6320-4 | 63 | 20 | 9.525 | 95 | 135 | 20 | 149 | 115 | 100 | 13.5 | M8×1 | 1×4 | 7404 | 19008 |
| SFU8010-4 | 80 | 10 | 6.35 | 105 | 145 | 20 | 98 | 125 | 110 | 13.5 | M8×1 | 1×4 | 4900 | 17366 |
| SFU8020-4 | 80 | 20 | 9.525 | 125 | 165 | 25 | 154 | 145 | 130 | 13.5 | M8×1 | 1×4 | 8403 | 25345 |
Note: Models marked ☆ in catalog are also available in left-hand thread. Suffix "-3" = 1×3 ball circuits; "-4" = 1×4 ball circuits.
Structural Types
Standard Flange Type (SFU)
Integral square or round flange with counterbored mounting holes allows direct bolting to equipment. The most widely specified variant for automation and CNC applications. Preload adjustment eliminates axial clearance without requiring additional hardware.
Cylindrical Type (SFU-R)
No flange; requires a dedicated nut housing. Reduces radial envelope for space-constrained assemblies or through-shaft mounting configurations. Preferred in compact automation modules and multi-axis stages.
Double-Nut / Extended Type (SFU-D)
Extended nut body with additional ball circulation turns (e.g., 3+3 turns). Increases dynamic load rating and rigidity for heavy-duty or high-cycle applications. Suitable when service life and stiffness outweigh compact form factor.
Why SFU Series - Technical Advantages for Engineers
External tube-type recirculation
Balls return through external steel tubes, enabling higher load capacity and smooth circulation at elevated speeds compared to internal-channel designs. The Recirculating Ball Screw Nut design keeps preload stable across the full stroke.
Gothic arch raceway geometry
45° four-point contact between ball and groove provides axial and radial load sharing. This geometry is what allows backlash to be eliminated through preload rather than tight tolerance fits alone.
Sealing
End-cap seals on both faces prevent contamination ingress. Recommended for environments with cutting fluid mist, metal dust, or particulate exposure.
Interchangeability
SFU nuts and screw shafts of matching specification are dimensionally interchangeable across our production batches, supporting stock rotation and field replacement without re-qualification.
Products Description
CNC Machine Tools
X/Y/Z axis feed drives, tool changers
Industrial Robots
Precision joint actuation, end-effector drives
Semiconductor Equipment
Wafer handling stages, inspection platforms
Medical / Lab Automation
Pipetting robots, diagnostic stage positioning
Laser Cutting / Engraving
Gantry positioning, focusing axis
planning cepteur3D Printing / Additive
Build platform Z-axis, high-speed X-Y heads
Manufacturing & Quality Assurance
Zhejiang Baili Guide Rail Manufacturing Co., Ltd. operates a 14,000 m² production facility in Lishui, Zhejiang Province, equipped with Japanese and German CNC grinding centers and a temperature- and humidity-controlled precision measurement room.
Key production controls for SFU nuts:
- Raw material: GCr15 bearing steel, incoming batch inspection
- Raceway grinding: CNC profile grinding to ±0.005 mm accuracy
- Hardness verification: HRC 58–62 per finished piece
- Dimensional inspection: CMM equipment in climate-controlled lab
- Preload testing: axial clearance measured and graded before dispatch
Accuracy grades C3, C5, C7, and C10 are produced and graded in-house. Grade certification documentation is available upon request for C5 and above.
From Baili - What B2B Buyers Can Expect
Direct manufacturer pricing
No trading company margin. Our facility in Lishui supplies customers across Europe, North America, and Southeast Asia direct from factory.
01
MOQ of 1 piece
Sample orders accepted. Standard models (SFU1204, SFU1605, SFU2005) typically ship within 7–15 days from stock.
02
OEM / custom specifications
Non-standard lead, extended nut body, modified flange pattern, or special material - submit drawings or a sample for engineering review.
03
Monthly capacity: 100,000+ sets
Across linear guide and ball screw product families. Volume pricing tiers available for quarterly blanket orders.
04
Technical support
Our engineering team can advise on nut selection, preload grade, compatibility with your ball screw shaft, and mounting configuration. Response within 24 hours on working days.
05
Frequently Asked Questions
Q: What preload grade should I specify for my application?
A: For general CNC milling or routing, C7 grade with light preload handles most requirements. For high-speed axes or applications requiring sub-0.01 mm repeatability - such as grinding machines or semiconductor stages - specify C5 or C3 with medium preload. Send us your axis speed (rpm), axial load, and accuracy requirement and we will recommend the appropriate grade.
Q: What is the lead time?
A: Standard SFU models (SFU1605, SFU2005, SFU2505) typically ship within 7–15 days. Custom specifications - modified flange pattern, non-standard lead, special material - require 25–30 days after drawing confirmation.
Q: Can SFU nuts be ordered separately from the ball screw shaft?
A: Yes, nuts are available independently. Provide your shaft diameter, lead, and required nut dimensions and we will confirm fit before processing your order.
Q: What is the minimum order quantity?
A: MOQ is 1 piece. Sample orders are accepted; outbound shipping costs are borne by the buyer. Volume pricing tiers are available for blanket orders - contact us with your quarterly forecast.
Q: Do you support OEM or custom specifications?
A: Yes. Non-standard lead, extended nut body, modified flange bolt pattern, or alternative steel grade are all feasible. Submit a drawing or a sample piece for engineering review. Our R&D team will confirm feasibility and provide a quote within 48 hours.
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