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When misalignment between a stepper motor shaft and a lead screw causes binding, vibration, or lost steps, the coupling is almost always the culprit. Engineers, makers, and machine builders who demand repeatable, low-backlash motion need a coupler that absorbs angular and parallel offset without transmitting shock loads back to the motor bearings. These flexible shaft couplings are designed for exactly that application.
Each coupler is machined from aluminum alloy with a helical-cut flexible body that accommodates angular misalignment of typically 1–3° and parallel offset of typically 0.2–0.5 mm. Available in two outer-diameter families — D40 mm (≈1.57 in) and D55 mm (≈2.17 in) — with lengths ranging from 55 mm to 80 mm (≈2.17–3.15 in). Shaft bore options span 12 mm to 28 mm (≈0.47–1.10 in), covering the most common stepper motor and servo shaft standards.
Typical use cases include CNC router Z-axis lead screw connections, FDM 3D printer Z-axis couplers replacing rigid spider couplings, and light-duty servo motor test rigs where flexible shaft coupling for stepper motor misalignment compensation is critical to print quality and machining accuracy.
The spiral cut pattern allows the coupler to flex under angular and parallel misalignment, reducing vibration transmission to motor bearings and extending motor service life.
Bore options from 12 mm to 28 mm (≈0.47–1.10 in) cover NEMA 17, NEMA 23, and many servo motor shaft standards — same-diameter and stepped-bore configurations available.
Each shaft end is secured by set screws that grip the shaft directly, providing positive torque transmission without relying solely on friction — suitable for both smooth and D-cut shafts.
D40 mm body suits compact NEMA 17 builds; D55 mm body handles higher-torque NEMA 23 applications. Select the coupler dimension that matches your motor frame and available clearance.
Available in quantities of 1, 2, 3, or 5 per order — ideal for stocking spares for multi-axis machines or ordering for a full printer farm build.
Standard OD and length dimensions match common aftermarket coupler footprints, making these a direct swap for worn or rigid couplings on most CNC and 3D printer frames.
| Coupler Body Material | Aluminum alloy |
|---|---|
| Coupler Type | Helical-cut flexible jaw coupler |
| Outer Diameter (OD) | D40 mm (≈1.57 in) / D55 mm (≈2.17 in) |
| Overall Length | 55 mm / 65 mm / 78 mm / 80 mm (≈2.17–3.15 in) |
| Shaft Bore Diameter | See variant options (12 mm–28 mm) |
| Bore Configuration | Same-diameter or stepped (see variant options) |
| Angular Misalignment Tolerance | Typically 1–3° |
| Parallel Offset Tolerance | Typically 0.2–0.5 mm |
| Clamping Method | Set screw (both shaft ends) |
| Finish | Natural anodized aluminum |
| Quantity per Order | See variant options (1 / 2 / 3 / 5 pcs) |
| Weight (per unit) | See variant options |
Match the shaft bore to your motor shaft diameter and lead screw diameter. For NEMA 17 motors (typically 5 mm shaft) paired with T8 lead screws (8 mm), select the 5 mm-to-8 mm bore variant. For same-shaft connections, choose a same-diameter bore. The coupler OD (D40 or D55) should fit within the clearance of your motor mount and frame.
The D55 mm × L78 mm and D55 mm × L80 mm variants are sized for NEMA 23 applications. The larger body diameter and longer clamping zone provide greater torque capacity than the D40 mm family. For high-duty-cycle or high-torque applications, confirm your motor's rated torque against the coupler's bore and set-screw clamping capacity.
Yes. The set-screw clamping design works with both round and D-cut shafts. For D-cut shafts, orient one set screw to bear against the flat for maximum grip and to prevent shaft rotation under load.
The helical-cut body typically accommodates angular misalignment of 1–3° and parallel (radial) offset of 0.2–0.5 mm. These values are conservative estimates for standard helical aluminum couplers of this size. Minimizing misalignment at installation will extend coupler life and reduce vibration.
The aluminum alloy body with anodized finish provides moderate corrosion resistance suitable for indoor workshop and enclosed machine environments. For prolonged exposure to moisture, salt air, or chemical vapors, consider applying a light protective coating or selecting a stainless-steel coupler variant.
Multi-axis CNC machines and 3D printers often require 2–3 couplers per build (X, Y, Z axes). Ordering a 2-, 3-, or 5-pack reduces per-unit cost and ensures you have spares on hand for maintenance. The 5-pack is particularly cost-effective for printer farm operators or workshop stock.
Insert each shaft fully into its respective bore end until it reaches the center stop. Tighten the set screws with an appropriate hex key (typically 2–3 mm) to the manufacturer's recommended torque — usually finger-tight plus a quarter turn for aluminum shafts, slightly firmer for steel shafts. Do not overtighten, as this can deform the bore or strip the set-screw thread.
