4mm Rigid Flange Coupling - Aluminum Shaft Connector for Robot Wheels

Specifications

• Shaft Bore Diameter: 4mm (H7 Tolerance)

• Material: Aluminum Alloy (Silver / Chrome Finish)

• Overall Height: ~12-13mm

• Cylinder Diameter (Hub): ~10mm

• Flange Diameter (Base): ~22mm

• Mounting Holes (Flange): 4 x M3 (Tapped)

• Mounting Pitch: ~16mm (Diagonal Center-to-Center)

• Shaft Locking: 2 x M3/M4 Grub Screws (Included)

• Weight: ~12g

Key Applications & Projects

• Robotics: Mounting 58mm/60mm Omni Wheels or Mecanum Wheels to JGA25-370 motors.

• RC Models: Attaching custom propellers or flywheels to 4mm brushless motor shafts.

• DIY Mechanisms: Creating a turntable by bolting a flat acrylic plate to a motor.

• Rotary Encoders: Connecting a code wheel to a shaft.

Virtual Technician: Installation Tips ⚠️

• Flat Spot Check: For the strongest hold, file a small "flat spot" on your motor shaft (D-Shaft). Align one of the grub screws with this flat spot to prevent the hub from slipping under high torque.

• Screw Length: When bolting a wheel to the flange, ensure your M3 screws are not too long. If they go through the flange and hit the motor body, the motor will jam.

• Loctite: Use a drop of Blue Threadlocker on the grub screws if your robot vibrates heavily.

Accessories

• Included: 1x 4mm Rigid Flange Coupling - Aluminum Shaft Connector, 2 x Grub Screws.

• Required (Sold Separately):

  • 4mm Shaft Motor (e.g., JGA25 Series)

  • M3 Mounting Screws (for attaching the wheel)

  • Allen Key (1.5mm or 2mm)

Frequently Asked Questions (FAQ)

1. Will this fit a NEMA 17 motor?

   • No. NEMA 17 motors usually have a 5mm shaft. You need a 5mm Flange Coupler.

2. Does it fit "Orange" BO Motors?

   • No. BO Motors have a specific dual-flat plastic shaft. This is for round metal shafts (4mm).

3. What size screws do I need to mount my wheel?

   • It requires M3 (3mm) Machine Screws.

4. How far apart are the holes?

   • The holes are usually spaced 16mm apart diagonally.

5. Is it made of plastic?

   • No, it is solid Aluminum Alloy.

6. Can I drill the hole to 5mm?

   • It is possible with a drill press, but difficult to keep centered manually. Buying the correct 5mm version is better.

7. Does it come with the Allen key?

   • Usually no. You will need a standard small metric Allen key set.

8. Can I use this for a saw blade?

   • Only for very small, low-power hobby blades. It is not safe for industrial cutting.

9. How many grub screws does it use?

   • It uses 2 grub screws at 90 degrees for a secure grip.

10. Is the finish shiny or matte?

    • Typically a shiny silver (chrome-like) finish.

11. Will it rust?

    • Aluminum does not rust, but it can oxidize slightly over years. It is generally very corrosion resistant.

12. Can I use superglue instead of screws?

    • Not recommended. The vibration will crack the glue. Always use the set screws.

13. What is the outer diameter of the base?

    • Approx 22mm.

14. Is this suitable for high RPM?

    • Yes, aluminum is balanced enough for typical DC motor speeds (up to 5000 RPM).

15. Can I connect two shafts with this?

    • No. This connects a Shaft to a Flat Surface. To connect Shaft-to-Shaft, use a "Flexible Coupler".

16. Does it fit JGA25-370 Motors?

    • Yes! This is the perfect size for those 4mm shaft geared motors.

17. What happens if I strip the grub screw?

    • You can tap it to the next size (M4) or buy replacement M3 grub screws.

18. Can I weld it?

    • No, you cannot weld aluminum easily to steel motor shafts.

19. Is the flange face perfectly flat?

    • Yes, it is machined flat to prevent wheel wobble.

20. Does it work on a D-Shaft?

    • Yes, perfect for D-Shafts. Align the screw to the flat part.