Oldham couplings (also known as cross slider couplings or sliding disc couplings) are essential components in precision motion control systems. With their unique sliding design, they provide zero backlash, low inertia, and excellent radial misalignment compensation – making them the ideal choice for servo motors, stepper motors, encoders, and resolvers.

This guide explains how Oldham couplings work, their key advantages, and how to select the right model for your application.

1. What Is an Oldham Coupling?

An Oldham coupling consists of:

• Two aluminum hubs – with axial grooves on their inner faces

• A center slider – engineering plastic (PA66) with matching slots at 90° on each side

As the coupling rotates, the center slider slides within the grooves of the hubs, accommodating radial (eccentricity) and angular misalignment while transmitting torque. The PA66 slider provides electrical insulation between the two shafts, preventing ground loops in sensitive applications. The clamping screw design provides even clamping force without shaft damage.

💡 Oldham couplings are widely used in servo motor, stepper motor, encoder, and resolver applications due to their zero backlash and excellent radial misalignment compensation.

2. Key Advantages of Oldham Couplings

3. Clamping vs Set Screw – Why Clamping is Superior

The DHC series features a clamping screw design which offers significant advantages over traditional set screw couplings:

✅ Choose clamping type (DHC) for applications requiring secure shaft fixation without damage, especially for precision servo and stepper motor connections.

4. Applications Where Oldham Couplings Excel

5. How to Select the Right Oldham Coupling

Step 1: Determine Your Torque Requirement

• Calculate the torque your application requires.

• Select a model with adequate torque capacity.

• DHC series covers up to 33 N·m.

Step 2: Match Shaft Diameters

• Measure your shaft diameters.

• Select a model with a bore range that accommodates your shafts.

• H7 bore tolerance is recommended for precision fit.

Step 3: Consider Space Constraints

• Measure available space for the coupling (outer diameter and length).

• DHC series offers compact sizes from 16 mm OD.

Step 4: Evaluate Misalignment

• Determine the expected radial and angular misalignment.

• Oldham couplings compensate for radial and angular misalignment.

Step 5: Consider Speed Requirements

• Verify the coupling’s maximum speed exceeds your operating speed.

• DHC series offers speeds up to 9000 RPM.

Step 6: Consider Electrical Isolation

• The PA66 slider provides electrical insulation – ideal for encoder applications.

Step 7: Select Fastening Type

• Clamping type (DHC) – even clamping force, no shaft damage.

6. Installation & Maintenance Tips

1. Clean shafts – Remove oil, grease, and debris before installation.

2. Check alignment – Even with misalignment compensation, keep within recommended limits.

3. Tighten clamping screws evenly – Use a torque wrench in a star pattern for even clamping force.

4. No lubrication required – Coupling is maintenance-free.

5. Periodic inspection – Check slider condition periodically.

6. Keep clean – Remove dust and debris to prevent premature wear.

7. Slider replacement – Replace slider without moving hubs.

7. Real‑World Example – Servo Motor Encoder Upgrade

A machine builder was experiencing position errors on a servo-driven system due to backlash in their existing coupling. The coupling also transmitted ground loop noise to the encoder, causing signal interference.

They switched to Apex Coupling DHC aluminum cross slider coupling (zero backlash, PA66 slider, clamping design). Results:

• Position errors eliminated – zero backlash

• Signal noise eliminated – PA66 slider provided electrical isolation

• Maintenance eliminated – no lubrication required

• Shaft protection – clamping design prevented shaft damage

• Accuracy improved – H7 precision bore

8. Selection Checklist

• □ 

  Type: DHC – aluminum cross slider (Oldham) coupling

• □ 

  Material: Aluminum hubs + PA66 slider

• □ 

  Fastening: Clamping type – even clamping force, no shaft damage

• □ 

  Backlash: Zero backlash – precision applications

• □ 

  Bore: H7 tolerance – match your shaft diameters

• □ 

  Misalignment: Radial and angular – verify capacity

• □ 

  Speed: Up to 9000 RPM – match your motor speed

• □ 

  Torque: Up to 33 N·m – ensure it exceeds your requirement

• □ 

  Maintenance: Maintenance-free – no lubrication

• □ 

  Application: Servo motors, stepper motors, encoders, 3D printers

9. Conclusion

The DHC aluminum cross slider coupling from Apex Coupling offers the perfect combination of zero backlash, high radial misalignment capacity, electrical insulation, and clamping fastening for precision motion control applications. With aluminum alloy hubs, imported PA66 slider, clamping screw fastening, and maintenance-free operation, it is the ideal solution for servo motors, stepper motors, encoders, and 3D printers.

👉 Need an Oldham coupling for your precision application? Contact us with your model, bore, and torque requirements.