If you are currently using Misumi UNCA (single) or UNCW (double) universal joints, you have a new, cost-effective alternative. The Apexcoupling G and GD series are precision-engineered universal joints that are fully interchangeable with UNCA and UNCW couplings – offering the same high quality, same dimensions, and same performance at factory-direct pricing.

This guide explains how the G/GD series compares to UNCA/UNCW, why it is a smart replacement choice, and how to select the right configuration for your application.

1. Quick Comparison: G/GD vs Misumi UNCA/UNCW

✅ Key advantages of G/GD: Larger angle capacity (45° vs 30°), multiple material options, and needle bearing option for higher speeds.

2. Why Replace UNCA/UNCW with G/GD?

Reason 1: Cost Savings

• Factory-direct pricing – no distributor markup

• Same quality, same dimensions – no design changes required

Reason 2: Larger Angle Capacity

• G/GD offers 45° per joint vs UNCA/UNCW standard 30°

• More flexibility in equipment design and installation

Reason 3: More Material Options

• Choose from 42CrMo, 40Cr, 40CrNi, 20CrMo, 20CrMnVB, SUS304, SUS316, aluminum alloy, or nylon

• UNCA/UNCW is limited to SCM415 alloy steel 

Reason 4: Needle Bearing Option (GZ/GDZ)

• Up to 4000 RPM – maintenance-free with lifetime lubrication

• UNCA/UNCW standard is plain bearing only

Reason 5: More Connection Options

• Keyway, hexagon hole, square hole, spline, flange – fully customizable

3. G Type (Single) – Replaces UNCA

The G type is a single universal joint designed for angular misalignment only. It is the direct replacement for Misumi UNCA.

Key specifications:

• Maximum angle: 45° per joint

• Plain bearing: up to 1000 RPM

• Needle bearing (GZ): up to 4000 RPM

• H7 bore tolerance

• Inner hole: 6–50 mm

Best for: Shafts that intersect at an angle on the same plane.

4. GD Type (Double) – Replaces UNCW

The GD type is a double universal joint designed for both angular misalignment and parallel offset. It is the direct replacement for Misumi UNCW.

Key specifications:

• Maximum angle: 45° per joint (90° total)

• Plain bearing: up to 1000 RPM

• Needle bearing (GDZ): up to 4000 RPM

• H7 bore tolerance

• Inner hole: 6–50 mm

Best for: Shafts that are both angled and offset.

5. Bearing Selection – Plain vs Needle

6. Material Options – Choose What Fits Your Environment

7. Customization – Beyond Standard UNCA/UNCW

The G/GD series offers customization that goes beyond standard UNCA/UNCW:

• Bore types: Keyway, hexagon hole, square hole, plain round

• Connection types: Internal spline, spline shaft, optical shaft + pin hole, optical shaft + keyway, square shaft, hexagonal shaft, small flange

• Materials: Multiple alloy steels, stainless steels, aluminum, nylon

• Surface treatments: Grinding, black oxide

8. Real‑World Example – Manufacturing Plant Upgrade

A manufacturing plant was using Misumi UNCA universal joints on their production line. Lead times were long, and costs were high. They switched to Apex Coupling G type universal joints (42CrMo, plain bearing, H7 bore). Results:

• Cost reduced by 35% – factory-direct pricing

• Lead time reduced – faster delivery

• Performance improved – 45° angle capacity vs 30°

• No design changes – drop-in replacement

9. Installation & Maintenance Tips

1. Check alignment – Even with misalignment compensation, keep angles ≤45° for optimal bearing life

2. Lubricate plain bearings – Regular lubrication extends service life

3. Needle bearings – Maintenance-free – no lubrication required

4. Inspect for wear – Check cross joint and bearings periodically

5. Dynamic balancing – For speeds above 1000 RPM, ensure the joint is balanced

10. Selection Checklist

• Configuration: G (single – replaces UNCA) or GD (double – replaces UNCW)

• Bearing: Plain (1000 RPM) or Needle – GZ/GDZ (4000 RPM)

• Material: Alloy steel, stainless steel, aluminum, or nylon

• Bore type: Keyway, hexagon, square, or plain

• Bore size: 6–50 mm – match your shaft diameter

• Connection type: Standard, spline, flange, or custom

• Surface: Grinding or black oxide

11. Conclusion

The G and GD precision universal joints from Apex Coupling offer a cost-effective, drop-in replacement for Misumi UNCA and UNCW couplings – with the added benefits of larger angle capacity (45° vs 30°), more material options, and needle bearing capability (4000 RPM) . With factory-direct pricing, H7 precision bore, and full customization, they are the smart choice for building material shops, manufacturing plants, machinery repair shops, and construction equipment.

👉 Need a UNCA/UNCW replacement? Contact us with your configuration and bore requirements.