PRODUCTS
CONTACT US
DNC Aluminum Rigid Clamping Coupling – Zero Backlash, High Rigidity
Model Number
Check below, custom
D16-L16-bore(4~6.35)
D16-L22-bore(4~6.35)
D20-L20-bore(4~10)
D20-L24-bore(4~10)
D25-L25-bore(5~12)
D25-L36-bore(5~12)
D32-L32-bore(6~16)
D32-L40-bore(6~16)
D40-L44-bore(8~20)
D50-L55-bore(10~25)
D68-L54-bore(15~35)
D68-L90-bore(15~35)
D82-L68-bore(19~45)
D82-L110-bore(19~45)
D95-L126-bore(22~60)
D105-L140-bore(30-60)
D120-L160-bore(35~70)
- Phone : +86 13431039760
- Wechat : +86 13431039760
- Whatsapp : +86 13431039760
- Email : ella@apexcoupling.com
Product Description
DNC Aluminum Rigid Clamping Coupling – Zero Backlash, High Rigidity for Servo & Stepper Motors
Factory Direct | High-Strength Aluminum Alloy | One-Piece Integrated Structure | Zero Backlash | High Torque & High Rigidity | Low Inertia | Clamping Screw Design | Anodized Finish | Maintenance-Free | OEM Customizable
The Apexcoupling DNC series is a high-precision rigid clamping coupling engineered for applications demanding zero backlash and maximum torsional rigidity. Featuring a one-piece integrated structure machined from high-strength aluminum alloy, this coupling provides a solid, backlash-free connection between two shafts. The clamping screw design ensures secure shaft fixation with even clamping force – without damaging the shaft surface. With high torque capacity, high rigidity, and low inertia, the DNC series is the ideal choice for servo motors, stepper motors, CNC machines, 3D printers, and precision positioning systems.
⚠️ Important: Rigid couplings do not accommodate any misalignment (radial, angular, or axial). The shafts must be perfectly aligned during installation to prevent bearing damage or shaft failure.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Brand | Apexcoupling |
| Model Series | DNC (Rigid Clamping Coupling) |
| Type | Rigid / Clamping |
| Structure | One-piece integrated |
| Material | High-strength aluminum alloy |
| Surface Treatment | Anodized |
| Backlash | Zero – no rotational clearance |
| Bore Tolerance | H7 |
| Outer Diameter Range | 16 – 63 mm |
| Length Range | 16 – 71 mm |
| Rated Torque | 5 – 115 N·m |
| Maximum Speed | 3500 – 9400 RPM (varies by model) |
| Fastening Method | Clamping screw |
| Screw Torque | 0.8 – 8 N·m |
| Misalignment Compensation | None – shafts must be perfectly aligned |
| Maintenance | None required – maintenance-free |
| Customization | OEM – custom bores and sizes |
| Applicable Industries | Building material shops, manufacturing plants, machinery repair shops, printing shops, construction works, servo motors, stepper motors, CNC machines |
| Place of Origin | Guangdong, China |
🔧 Custom bores and sizes available. Contact us with your specifications.
DNC Series – Model Range & Specifications
| Model | Outer Diameter (D) mm | Length (L) mm | Bore Range (d) mm | Screw Torque (N·m) | Max Speed (RPM) | Set Screw Size |
|---|---|---|---|---|---|---|
| DNC-16×16 | 16 | 16 | 3,4,5,6,6.35,7,8 | 0.8 | 9400 | M2.5 |
| DNC-16×24 | 16 | 24 | 3,4,5,6,6.35,7,8 | 0.8 | 9400 | M2.5 |
| DNC-20×20 | 20 | 20 | 4,5,6,6.35,7,8,9,9.525,10 | 0.8 | 9400 | M2.5 |
| DNC-20×30 | 20 | 30 | 4,5,6,6.35,7,8,9,9.525,10 | 0.8 | 9400 | M2.5 |
| DNC-25×25 | 25 | 25 | 5,6,6.35,7,8,9,9.525,10,12 | 1.2 | 9400 | M3 |
| DNC-25×36 | 25 | 36 | 5,6,6.35,7,8,9,9.525,10,12 | 1.2 | 9400 | M3 |
| DNC-28.5×38 | 28.5 | 38 | 6,6.35,7,8,9,9.525,10,11,12,14 | 2.5 | 9000 | M4 |
| DNC-32×32 | 32 | 32 | 6,6.35,7,8,9,9.525,10,12,12.7,14,15,16 | 2.5 | 8400 | M4 |
| DNC-32×41 | 32 | 41 | 6,6.35,7,8,9,9.525,10,12,12.7,14,15,16 | 2.5 | 8400 | M4 |
| DNC-40×44 | 40 | 44 | 8,9,9.525,10,11,12,12.7,14,15,16,17,18,19,20 | 5 | 6000 | M5 |
| DNC-40×52 | 40 | 52 | 8,9,9.525,10,11,12,12.7,14,15,16,17,18,19,20 | 5 | 6000 | M5 |
| DNC-50×55 | 50 | 55 | 10,11,12,12.7,14,15,16,17,18,19,20,22,24,25 | 8 | 4800 | M6 |
| DNC-50×66 | 50 | 66 | 10,11,12,12.7,14,15,16,17,18,19,20,22,24,25 | 8 | 4800 | M6 |
| DNC-63×71 | 63 | 71 | 10,11,12,12.7,14,15,16,17,18,19,20,22,24,25,28,30,32,35 | 8 | 3500 | M6 |
📐 Additional sizes and custom dimensions available upon request. Contact our engineering team for custom sizing.
Product Structure
One-Piece Integrated Body – Precision-machined from high-strength aluminum alloy for maximum rigidity.
Clamping Screws – Provide even clamping force around the shaft without damaging the surface.
Smooth Bore – Precision-machined bore with H7 tolerance for accurate shaft fit.
💡 How it works: The DNC rigid coupling is a one-piece clamping-type coupling that creates a solid, backlash-free connection between two perfectly aligned shafts. The clamping screws are tightened evenly to secure the coupling to both shafts, creating a single rigid unit that transmits torque with zero lost motion. Unlike flexible couplings, rigid couplings have no element to absorb misalignment – they rely on perfect shaft alignment for proper operation.
Clamping vs Set Screw – Why Clamping is Superior
The DNC series features a clamping screw design which offers significant advantages over traditional set screw couplings:
| Feature | Clamping Type (DNC) | Set Screw Type |
|---|---|---|
| Shaft damage | None – even clamping force | Potential – point contact can mar shafts |
| Clamping force | Uniform – distributed around shaft | Concentrated – at set screw points |
| Shaft retention | Superior – full circumferential grip | Moderate – point contact only |
| Installation | Easy – even screw tightening | Simple – screw tightening |
| Best for | Precision, sensitive shafts, high torque | General applications, cost-sensitive |
✅ Choose clamping type (DNC) for applications requiring secure shaft fixation without damage, especially for precision servo and stepper motor connections.
Product Features & Advantages
| Advantage | Benefit |
|---|---|
| Zero Backlash | No rotational clearance – precise positioning for servo and stepper motors |
| One-Piece Integrated Structure | Maximum rigidity – no moving parts, no wear, long service life |
| High Torsional Rigidity | No angular deflection under load – maintains system accuracy |
| High Torque Capacity | 5-115 N·m – handles demanding applications |
| Low Inertia | Lightweight aluminum design enables high-speed operation |
| Clamping Screw Design | Even clamping force, no shaft damage – superior to set screw types |
| H7 Precision Bore | High concentricity and accurate shaft fit – reduces vibration |
| Anodized Finish | Enhanced corrosion resistance and professional appearance |
| Maintenance-Free | No lubrication required – reduces operating costs |
| High Speed Capability | Up to 9400 RPM – suitable for high-speed applications |
| OEM Customization | Custom bores and sizes available |
Applications
Servo Motors – High-precision motion control, zero backlash requirement
Stepper Motors – Accurate positioning, no lost motion
CNC Machines – Feed drives, positioning systems
3D Printers – Precision shaft connections
Robotics – Joint drives, precision motion
Encoders – Precision position feedback systems
Printing Shops – Register control, high-speed operation
Automation Equipment – Pick-and-place systems, indexing tables
Precision Positioning Systems – XY tables, linear stages
Important Installation Note – Perfect Alignment Required
⚠️ Rigid couplings do NOT accommodate any misalignment. The shafts must be perfectly aligned during installation.
| Misalignment Type | Allowable Tolerance |
|---|---|
| Radial (eccentricity) | 0 mm – must be fully adjusted |
| Angular | 0° – shafts must be collinear |
| Axial | 0 mm – no end play allowed |
💡 Installation tip: Use a dial indicator or laser alignment tool to ensure perfect shaft alignment before tightening the clamping screws. Improper alignment will cause premature bearing failure and shaft damage.
Why Choose Apex Coupling for DNC Rigid Couplings?
| Advantage | Description |
|---|---|
| Factory Direct | Competitive B2B pricing – no middlemen |
| Premium Aluminum Alloy | High strength, lightweight, corrosion-resistant |
| Clamping Design | Even clamping force, no shaft damage |
| Zero Backlash | Precise positioning for servo and stepper motors |
| High Torsional Rigidity | No angular deflection – maintains system accuracy |
| Low Inertia | High-speed capability – quick starts and stops |
| One-Piece Construction | Maximum rigidity – no wear parts |
| H7 Precision Bore | High concentricity and accurate shaft fit |
| Maintenance-Free | No lubrication required – reduces operating costs |
| OEM Customization | Custom bores and sizes available |
FAQ
Q: What is a rigid clamping coupling?
A: A rigid clamping coupling is a one-piece coupling that creates a solid, backlash-free connection between two perfectly aligned shafts. It uses clamping screws to secure the coupling to both shafts, transmitting torque with zero lost motion.
Q: Does the coupling have backlash?
A: No. The DNC series features zero backlash – no rotational clearance, ensuring precise positioning for servo and stepper motors.
Q: What is the advantage of the clamping screw design?
A: The clamping screw design provides even clamping force around the shaft without damaging it – offering superior shaft retention compared to set screw designs.
Q: Can the coupling compensate for misalignment?
A: No. Rigid couplings do not accommodate any misalignment (radial, angular, or axial). The shafts must be perfectly aligned during installation.
Q: Is the coupling maintenance-free?
A: Yes. The one-piece integrated structure has no moving parts or wear items – maintenance-free operation.
Q: What are the common applications?
A: Servo motors, stepper motors, CNC machines, 3D printers, robotics, encoders, printing equipment, and precision positioning systems.
Q: Can I get a custom coupling?
A: Yes. We offer OEM customization – custom bores and sizes available.
Request a Quote
Send us your model (e.g., DNC-25×25), bore size, and application details. Our engineers will recommend the optimal model and provide a quotation within 24 hours.
DNC coupling
Aluminum rigid coupling
Rigid clamping coupling
Zero backlash coupling
Servo motor coupling
High rigidity coupling
DNC-16×16 DNC-20×20 DNC-25×25 DNC-32×32 DNC-40×44 DNC-50×55 DNC-63×71
Product Show
Aluminum rigid coupling
