Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
When a misaligned or loose shaft coupling causes your CNC router to skip steps or your 3D printer to produce layer shifts, the fix starts at the coupler. This flexible shaft coupling is designed for engineers, makers, and workshop professionals who need a reliable mechanical connection between motor shafts and lead screws — without the vibration and backlash that rigid couplings introduce.
Each coupler features a set-screw locking design machined from aluminum alloy, with an outer diameter (D) of 12mm, 15mm, or 16mm and a body length (L) of 18mm to 23mm depending on the selected variant. Bore sizes (d1 × d2) range from 2mm × 2mm up to 6.35mm × 6.35mm, accommodating both metric and imperial shaft combinations. Available individually (1 Pcs) or in workshop packs (10 Pcs).
Typical applications include flexible shaft coupling for CNC router Z-axis lead screws, stepper motor to ball screw connections in 3D printer builds, and shaft-to-shaft coupling in small automation and robotics projects where angular misalignment compensation is required.
Dual set screws grip each shaft independently, preventing rotational slip under load without requiring adhesive or press-fit assembly.
Supports bore combinations from 2mm × 2mm to 6.35mm × 6.35mm, covering common metric and imperial shaft sizes used in CNC and 3D printing.
The helical-cut body absorbs minor angular and parallel misalignment between shafts, reducing vibration transmission to the frame and print bed.
Lightweight yet rigid enough for continuous-duty stepper motor applications; resists deformation under the torsional loads typical of lead-screw drives.
Order one coupler for a repair or a 10-pack for a full machine build or spare-parts inventory — same bore spec, better per-unit value in bulk.
Choose D12 × L18mm, D15 × L20mm, D16 × L20mm, or D16 × L23mm to match your motor mount clearance and coupling hub requirements.
| Coupling Type | Set-screw flexible (helical-cut) |
|---|---|
| Outer Diameter (D) | 12mm / 15mm / 16mm — See variant options |
| Body Length (L) | 18mm / 20mm / 23mm — See variant options |
| Bore d1 (Motor Side) | 2mm / 3mm / 3.17mm / 4mm / 5mm / 6mm / 6.35mm — See variant options |
| Bore d2 (Lead Screw Side) | 2mm / 3mm / 3.17mm / 4mm / 5mm / 6mm / 6.35mm — See variant options |
| Material | Aluminum alloy |
| Fastening Method | Set screw (hex key tightened) |
| Quantity per Order | 1 Pcs or 10 Pcs — See variant options |
| Shaft Compatibility | Metric and imperial shaft diameters |
| Typical Application | CNC router, 3D printer, stepper motor, lead screw, automation |
| Weight | See variant options |
Measure the shaft diameter on your motor output (d1) and the shaft diameter on your lead screw or driven component (d2). Select the variant whose d1 × d2 matches those measurements. For example, a NEMA 17 stepper with a 5mm shaft connected to a 5mm lead screw requires a 5mm × 5mm bore. If your shafts are different sizes, choose a stepped bore variant such as 5mm × 8mm.
The outer diameter must clear your motor mount and any surrounding hardware. D12mm is the most compact option, suited for tight enclosures. D15mm and D16mm offer more grip surface and are common in standard CNC builds. The body length (L) affects how much misalignment the coupler can absorb — longer bodies (L23mm) tolerate slightly more angular offset than shorter ones (L18mm).
Yes. The helical cut in the coupler body allows it to flex under load, compensating for minor angular misalignment (typically up to 1–3°) and small amounts of parallel offset. It is not designed for large misalignments — always align shafts as closely as possible during installation to maximize coupler lifespan and minimize vibration.
Yes. NEMA 17 motors typically have a 5mm output shaft, and NEMA 23 motors commonly use 6.35mm (1/4") shafts. Both shaft sizes are available as bore options in this listing. Select the bore combination that matches your motor shaft and lead screw diameter.
The dual set-screw design provides a firm mechanical grip on each shaft when properly torqued with a hex key. For best results, ensure shaft surfaces are clean and free of oil before tightening. Periodically check set screw tightness during the first few hours of operation, as initial seating can cause slight loosening.
The 1 Pcs option is ideal for a single-axis repair or replacement. The 10 Pcs pack is suited for full machine builds (e.g., a 3-axis CNC router requires at least 3 couplers), workshop stock, or group orders. The 10-pack offers a lower per-unit cost compared to buying individually.
Both share the same 16mm outer diameter. The L23mm variant has a longer body, which provides slightly more flexibility and a larger bore-to-bore distance — useful when your motor shaft and lead screw have a small gap between them, or when you need additional misalignment tolerance. The L20mm is more compact and fits tighter motor-to-screw configurations.
