10mm to 10mm Aluminum Flexible Shaft Coupler - CNC Stepper Motor Joint

Specifications

• Coupling Type: Flexible Helical Beam (Spiral Cut)

• Bore 1 Diameter (d1): 10mm

• Bore 2 Diameter (d2): 10mm

• Outer Diameter (D): 19mm

• Total Length (L): 25mm

• Material: Aluminum Alloy

• Fixing Type: 4x M4 Set Screws

• Rated Torque: ~1.2 N.m

• Max Rotational Speed: ~19,000 RPM

• Backlash: Zero Backlash Design

Key Applications and Projects

• DIY CNC Routers: Connecting high-torque NEMA 23 stepper motors to the X and Y axis ball screws on custom aluminum extrusion milling machines.

• Large Format 3D Printers: Eliminating "Z-Wobble" (visible horizontal banding on 3D prints) by decoupling the heavy Z-axis motors from slightly bent 10mm lead screws.

• Automated Camera Sliders: Providing incredibly smooth, vibration-free rotary motion from a motor into the driving belt pulley system.

Unlock New Capabilities (Project Evolution) The Flawless Z-Axis Upgrade: If you are building a custom CNC machine and experiencing loud grinding noises or stalled motors, your axes are binding. Evolve your mechanics! Throw away those cheap, solid brass couplers. Install these aluminum flexible couplers, but follow the golden rule of assembly: Leave a 2mm gap! When you insert the motor shaft into the bottom, and the ball screw into the top, make sure the two steel rods do not physically touch each other inside the coupler. Leaving a small air gap allows the helical spring to do its job, resulting in a machine that glides silently and never misses a step!

Package Includes:

• 1 x 10 mm to 10 mm Aluminium Flexible Coupler

• 4 x M4 Set Screws (Pre-installed in the collar)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What is the inner diameter of this coupler? Both sides of this specific coupler are bored to exactly 10mm.

2. What are the outer dimensions of the aluminum cylinder? It has an outer diameter (OD) of 19mm and a total length of 25mm.

3. What material is it made of? It is machined from a solid block of high-strength aluminum alloy.

4. Why does it have a spiral cut in the middle? The spiral cut turns the solid aluminum into a helical beam (like a very stiff spring). This provides the flexibility needed to absorb slight misalignments between the motor and the screw.

5. Will this eliminate "Z-wobble" on my 3D printer? Yes, it drastically reduces Z-wobble. By flexing, the coupler absorbs the orbital wobble of a bent lead screw, preventing those forces from pushing the 3D printer's hotend around.

6. Does it fit a standard NEMA 17 stepper motor? Generally, no. Standard NEMA 17 motors have a 5mm output shaft. You would need a 5mm-to-10mm coupler. This 10mm-to-10mm coupler is typically for larger NEMA 23 motors.

7. How does it grip the metal shafts? It uses four M4 set screws (grub screws). You slide the shafts in and tighten the screws down against the metal rods to lock them in place.

8. What tool do I need to tighten the screws? You will need a standard metric hex key (Allen wrench), typically 2mm or 2.5mm depending on the exact M4 screw batch.

9. Can I use this for high-torque industrial applications? It is rated for approximately 1.2 N.m of torque. It is excellent for hobbyist and prosumer CNCs, but it is not intended for massive industrial spindle drives that generate immense sheer forces.

10. Can it handle axial (push/pull) loads? It can handle minor axial loads, but you should not rely on the coupler to hold the weight of a heavy Z-axis. The lead screw should be supported by a thrust bearing (like a BK12 block) to take the axial load off the coupler.

11. Should the motor shaft and lead screw touch inside the coupler? No! This is a critical assembly error. You must leave a 1mm to 2mm gap between the two shafts inside the center of the coupler so the spiral section has physical room to flex.

12. Does this part require lubrication? No. It is a single-piece aluminum component with no internal moving bearings. Keep it dry and clean.

13. Can I use this to connect a 10mm motor to an 8mm lead screw? No, both sides of this specific model are exactly 10mm. You would need a "10mm to 8mm" variant for that specific setup.

14. Is this coupler prone to "backlash"? No. Helical beam couplings are specifically prized for having extremely low to zero backlash, making them perfect for precision CNC routing where directional changes must be instantaneous.

15. Can I drill the hole out to a larger 12mm size? It is highly discouraged. Drilling it out by hand will ruin the concentricity of the coupler, causing severe vibration and wobble at high speeds.

16. Are the set screws included? Yes, the four M4 set screws come pre-threaded into the aluminum collar.

17. What happens if I over-tighten the set screws? Because the coupler is made of aluminum (which is softer than steel), over-tightening the steel set screws can strip the aluminum threads. Tighten them firmly, but do not force them.

18. Should I use threadlocker on the screws? Yes. CNC machines vibrate heavily. Applying a small drop of blue (removable) Loctite to the set screws ensures they do not vibrate loose during a long carving job.

19. Does this work well with ball screws? Yes, it pairs excellently with popular ball screws (like the SFU1204 or SFU1605) that feature a machined 10mm end for motor coupling.

20. Will it rust if I use cutting fluid or water coolants on my CNC? Aluminum does not rust like steel does. However, prolonged exposure to harsh chemical coolants can cause mild surface oxidation. It is generally highly resistant to standard workshop environments.