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When misalignment between motor and driven shaft causes vibration, premature wear, or lost motion in your CNC machine, 3D printer, or automation rig, a rigid coupling simply won't cut it. These flexible shaft couplers are engineered for DIYers, machinists, and automation builders who need reliable torque transmission even when shafts are slightly offset, angular, or axially displaced.
Each coupler is machined from 40Cr alloy steel — a chromium-alloyed structural steel known for its tensile strength, toughness, and resistance to fatigue. Available in single-joint (Type A) and double-joint (Type B) configurations, sizes span inner diameters from 6 mm (~0.24 in) to 20 mm (~0.79 in), outer diameters from 12 mm to 42 mm, and lengths from 31 mm (~1.22 in) to 94 mm (~3.70 in). The 07G Type B variant features a black surface treatment for added corrosion resistance.
Typical applications include CNC router spindle-to-motor connections, stepper motor shaft coupling for 3D printer Z-axis drives, servo motor linkages in robotic arms, and flexible universal joint replacement in light industrial machinery. The multi-pack options (1, 2, 3, 5, or 10 pcs) make these couplers practical for both single-machine repairs and workshop stock.
Machined from chromium-alloyed 40Cr steel for high tensile strength, fatigue resistance, and long service life under cyclic torque loads.
Type A single-joint couplers handle moderate angular misalignment; Type B double-joint couplers accommodate larger offset angles for more demanding drive layouts.
Inner diameters from 6 mm to 20 mm and lengths from 31 mm to 94 mm cover the most common CNC motor and servo shaft sizes in one product family.
The largest double-joint variant features a black oxide or coating finish that improves surface corrosion resistance and reduces light reflection in precision setups.
Order 1, 2, 3, 5, or 10 pieces per SKU — ideal for single repairs, spare-parts kits, or stocking a workshop with matched couplers across multiple machines.
Bores are machined to close tolerances to minimize runout and ensure concentric shaft engagement, reducing vibration at operating speeds.
| Material | 40Cr Alloy Steel |
|---|---|
| Joint Type | Single Joint (Type A) / Double Joint (Type B) |
| Inner Diameter (ID) Range | 6 mm – 20 mm (0.24 in – 0.79 in) |
| Outer Diameter (OD) Range | 12 mm – 42 mm (0.47 in – 1.65 in) |
| Length (L) Range | 31 mm – 94 mm (1.22 in – 3.70 in) |
| Surface Finish | Natural machined (Type A) / Black treated (07G Type B) |
| Pack Quantity Options | 1 / 2 / 3 / 5 / 10 pcs |
| Torque Capacity | See variant options |
| Max RPM | See variant options |
| Weight (per piece) | See variant options |
Type A single-joint couplers are suited for applications with small angular misalignment (typically up to ~5°) between the motor and driven shaft. Type B double-joint couplers can handle larger angular offsets and are better for layouts where the motor and shaft centerlines cannot be closely aligned. If your setup has significant parallel or angular offset, choose Type B.
Measure your motor output shaft diameter (the ID you need) and the driven shaft diameter. Then check the OD to confirm it clears your housing or frame. The variant names list ID × OD × L in millimeters — for example, "ID10 x OD20 x L42mm" means a 10 mm bore, 20 mm outer diameter, and 42 mm total length.
40Cr is a chromium-alloyed structural steel with a tensile strength typically in the range of 900–1100 MPa after heat treatment. It is widely used in mechanical transmission components, shafts, and couplings for light to medium industrial loads. For very high-torque or shock-load applications, verify the specific torque rating of the variant you select against your system requirements.
40Cr steel is not stainless and will oxidize if exposed to moisture without protection. The standard Type A variants have a natural machined finish — apply a light machine oil or grease if used in humid environments. The 07G Type B variant includes a black surface treatment that provides additional corrosion resistance for exposed installations.
Yes. These flexible shaft couplers are commonly used on 3D printer Z-axis lead screw drives where the stepper motor shaft and lead screw may have slight misalignment. Select the variant whose ID matches your stepper motor shaft diameter (typically 5 mm, 6.35 mm, or 8 mm) — the ID8 variants are a common fit for NEMA 17 and NEMA 23 motors.
The GD-suffix variants (01GD, 1GD) have a longer overall length (L58 mm and L68 mm respectively) compared to their standard counterparts at the same ID and OD. The extended length provides more flexibility and a longer working section, which can be useful when greater axial travel or a softer coupling action is needed between the motor and driven shaft.
Yes. When you select a pack quantity of 2, 3, 5, or 10 pcs, all pieces in the pack are identical — same type, same ID × OD × L dimensions. Multi-packs are priced at a lower per-unit cost than single-piece orders, making them economical for workshop stock or multi-machine builds.
