{"product_id":"flexible-coupling-coupler-connector-3mm-4mm-6mm-bore","title":"3mm 4mm 6mm for Car Wheels Tires Shaft Motor Flexible Coupling Coupler Connector","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\n  \u003cdiv class=\"hdiy-overview\"\u003e\n    \u003ch2\u003eFlexible Shaft Coupling Coupler — Reliable Connection for Motors, Wheels \u0026amp; DIY Drives\u003c\/h2\u003e\n    \u003cp\u003eWhen a misaligned or loose shaft connection causes vibration, slippage, or premature wear in your RC car, robotics project, or DIY motor drive, the fix starts with the right flexible coupling coupler. This connector is designed for hobbyists, makers, and engineers who need a dependable, low-backlash shaft-to-shaft link without machining custom parts.\u003c\/p\u003e\n    \u003cp\u003eEach flexible coupling coupler is machined from aluminum alloy with a spider-jaw or beam-cut flexible body, available in bore sizes of 3 mm (~0.118 in), 4 mm (~0.157 in), and 6 mm (~0.236 in). The outer diameter is typically 19–25 mm (0.75–0.98 in) and overall length typically 25–30 mm (0.98–1.18 in), depending on bore size. Sold individually (1 pcs), in pairs (2 pcs), or in sets of four (4 pcs).\u003c\/p\u003e\n    \u003cp\u003eTypical use cases include connecting stepper motor shafts to lead screws in CNC routers, linking DC motor output shafts to RC car wheel axles, and coupling encoder shafts in robotics and automation rigs — all scenarios where a rigid coupling would crack under angular or parallel misalignment.\u003c\/p\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-compat\"\u003e\n    \u003cspan class=\"hdiy-compat-icon\"\u003e⚙️\u003c\/span\u003e\n    \u003cstrong\u003eCompatible with:\u003c\/strong\u003e 3 mm, 4 mm, and 6 mm round shafts — including stepper motors, DC gear motors, RC wheel axles, lead screws, and encoder shafts. Both shaft ends can be the same or different bore sizes (check variant options for mixed-bore availability).\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-features\"\u003e\n    \u003ch2\u003e✅ Key Features of These Flexible Shaft Coupling Couplers\u003c\/h2\u003e\n    \u003cdiv class=\"hdiy-list\"\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔩\u003c\/span\u003e\n        \u003cstrong\u003eThree Bore Sizes Available\u003c\/strong\u003e\n        \u003cp\u003eChoose 3 mm, 4 mm, or 6 mm bore to match your motor shaft or axle diameter exactly — no adapters needed.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔧\u003c\/span\u003e\n        \u003cstrong\u003eAbsorbs Misalignment\u003c\/strong\u003e\n        \u003cp\u003eThe flexible body accommodates angular, parallel, and axial misalignment, reducing vibration and protecting bearings in your drivetrain.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🏎️\u003c\/span\u003e\n        \u003cstrong\u003eRC Car \u0026amp; Robotics Ready\u003c\/strong\u003e\n        \u003cp\u003eSized for common hobby and maker shaft standards — fits RC car wheel hubs, robot drive trains, and small CNC axis drives.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e⚖️\u003c\/span\u003e\n        \u003cstrong\u003eLightweight Aluminum Construction\u003c\/strong\u003e\n        \u003cp\u003eMachined aluminum alloy body keeps rotating mass low while providing sufficient torque transmission for hobby-grade and light industrial applications.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e🔒\u003c\/span\u003e\n        \u003cstrong\u003eSet-Screw Clamping\u003c\/strong\u003e\n        \u003cp\u003eHex set screws on each jaw clamp firmly to the shaft, preventing slippage under load without permanent modification to your shafts.\u003c\/p\u003e\n      \u003c\/div\u003e\n      \u003cdiv\u003e\n        \u003cspan class=\"hdiy-icon\"\u003e📦\u003c\/span\u003e\n        \u003cstrong\u003eFlexible Quantity Options\u003c\/strong\u003e\n        \u003cp\u003eOrder 1, 2, or 4 pieces per purchase — ideal whether you need a single replacement or a full set for a multi-axis build.\u003c\/p\u003e\n      \u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-table-wrap\"\u003e\n    \u003ch2\u003e📐 Technical Specifications — Flexible Shaft Coupling Coupler\u003c\/h2\u003e\n    \u003ctable\u003e\n      \u003ctbody\u003e\n        \u003ctr\u003e\n\u003cth\u003eBore Size Options\u003c\/th\u003e\n\u003ctd\u003e3 mm \/ 4 mm \/ 6 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eAluminum alloy\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOuter Diameter\u003c\/th\u003e\n\u003ctd\u003eTypically 19–25 mm (0.75–0.98 in) — See variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eOverall Length\u003c\/th\u003e\n\u003ctd\u003eTypically 25–30 mm (0.98–1.18 in) — See variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eClamping Method\u003c\/th\u003e\n\u003ctd\u003eHex set screw\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eCoupling Type\u003c\/th\u003e\n\u003ctd\u003eFlexible jaw \/ beam-cut\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eNatural aluminum (anodized finish may vary)\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eMax Shaft Misalignment\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eQuantity per Order\u003c\/th\u003e\n\u003ctd\u003e1 pcs \/ 2 pcs \/ 4 pcs\u003c\/td\u003e\n\u003c\/tr\u003e\n        \u003ctr\u003e\n\u003cth\u003eCompatible Shaft Types\u003c\/th\u003e\n\u003ctd\u003eRound D-shaft and round shaft\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003c\/tbody\u003e\n    \u003c\/table\u003e\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-faq\"\u003e\n    \u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow do I choose the right bore size for my motor shaft?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eMeasure your motor output shaft diameter with a caliper. Select the bore size that matches: 3 mm for micro motors and small encoders, 4 mm for common hobby DC and stepper motors, and 6 mm for larger gear motors and RC car axles. If your two shafts are different diameters, contact us to confirm mixed-bore availability.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan this coupler handle angular misalignment between two shafts?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes. The flexible jaw or beam-cut design absorbs angular misalignment (typically up to 1–3°), parallel offset, and minor axial movement. This protects motor bearings and reduces vibration in your drivetrain. For severe misalignment, realign your mounts first for best results.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eWill the set screws hold securely under load without damaging my shaft?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe hex set screws clamp firmly to round shafts and provide reliable torque transmission for hobby-grade and light-duty applications. For D-shafts, the flat face gives extra grip. Tighten with the appropriate hex key to the recommended torque — over-tightening on very thin shafts (3 mm) can cause indentation, so apply firm but controlled force.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eIs this coupling suitable for RC car wheel and tire axle connections?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eYes — the 4 mm and 6 mm bore variants are commonly used to connect DC motor shafts to RC car wheel hubs and tire axles. The lightweight aluminum body minimizes unsprung weight, and the flexible element absorbs road-induced vibration that would otherwise stress the motor bearings.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow corrosion-resistant is the aluminum body?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eAluminum alloy offers good natural corrosion resistance for indoor and sheltered outdoor use. If your application involves moisture or humidity (e.g., outdoor robotics or marine RC), consider applying a light coat of corrosion-inhibiting spray to the coupling body. The anodized finish (where present) adds an additional protective layer.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eCan I use one coupler to connect shafts of two different diameters?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eThe listed variants feature the same bore on both ends. If you need to connect a 3 mm shaft to a 6 mm shaft, for example, please contact us to confirm whether a mixed-bore variant is available, or consider using a shaft adapter in combination with this coupler.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary\u003eHow many pieces should I order for a multi-axis CNC or robot build?\u003c\/summary\u003e\n      \u003cdiv class=\"hdiy-faq-body\"\u003e\u003cp\u003eFor a 3-axis CNC router, you typically need one coupler per axis (3 total). For a 4-wheel-drive robot, you may need 4 couplers. The 4 pcs quantity option offers the best per-unit value for multi-axis builds. Mix bore sizes across separate orders to match each axis's shaft diameter.\u003c\/p\u003e\u003c\/div\u003e\n    \u003c\/details\u003e\n\n  \u003c\/div\u003e\n\n  \u003cdiv class=\"hdiy-cta\"\u003e\n    🛒 Select your Bore Size and quantity above, then add to cart.\n  \u003c\/div\u003e\n\n\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How do I choose the right bore size for my motor shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Measure your motor output shaft diameter with a caliper. Select the bore size that matches: 3 mm for micro motors and small encoders, 4 mm for common hobby DC and stepper motors, and 6 mm for larger gear motors and RC car axles.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can this coupler handle angular misalignment between two shafts?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes. The flexible jaw or beam-cut design absorbs angular misalignment (typically up to 1–3°), parallel offset, and minor axial movement, protecting motor bearings and reducing vibration.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Will the set screws hold securely under load without damaging my shaft?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"The hex set screws clamp firmly to round shafts for reliable torque transmission in hobby-grade and light-duty applications. Tighten with the appropriate hex key — apply firm but controlled force, especially on 3 mm shafts.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Is this coupling suitable for RC car wheel and tire axle connections?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Yes — the 4 mm and 6 mm bore variants are commonly used to connect DC motor shafts to RC car wheel hubs and tire axles. The lightweight aluminum body minimizes unsprung weight.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How corrosion-resistant is the aluminum body?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Aluminum alloy offers good natural corrosion resistance for indoor and sheltered outdoor use. For moisture-prone environments, apply a light corrosion-inhibiting spray. An anodized finish adds additional protection where present.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"Can I use one coupler to connect shafts of two different diameters?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"Listed variants feature the same bore on both ends. For mixed-bore connections (e.g., 3 mm to 6 mm), contact us to confirm availability or use a shaft adapter in combination.\"\n      }\n    },\n    {\n      \"@type\": \"Question\",\n      \"name\": \"How many pieces should I order for a multi-axis CNC or robot build?\",\n      \"acceptedAnswer\": {\n        \"@type\": \"Answer\",\n        \"text\": \"A 3-axis CNC router typically needs 3 couplers (one per axis). A 4WD robot needs 4. The 4 pcs quantity option offers the best per-unit value for multi-axis builds.\"\n      }\n    }\n  ]\n}\n\u003c\/script\u003e","brand":"HomeDIYer","offers":[{"title":"3 mm \/ 1 pcs","offer_id":52421908693266,"sku":"PENGJSCS00685x1","price":2.71,"currency_code":"USD","in_stock":true},{"title":"4 mm \/ 1 pcs","offer_id":52421908726034,"sku":"PENGJSCS00687x1","price":2.71,"currency_code":"USD","in_stock":true},{"title":"6 mm \/ 1 pcs","offer_id":52421908758802,"sku":"PENGJSCS00686x1","price":2.92,"currency_code":"USD","in_stock":true},{"title":"3 mm \/ 2 pcs","offer_id":52421908791570,"sku":"PENGJSCS00685x2","price":4.61,"currency_code":"USD","in_stock":true},{"title":"4 mm \/ 2 pcs","offer_id":52421908824338,"sku":"PENGJSCS00687x2","price":4.61,"currency_code":"USD","in_stock":true},{"title":"6 mm \/ 2 pcs","offer_id":52421908857106,"sku":"PENGJSCS00686x2","price":4.88,"currency_code":"USD","in_stock":true},{"title":"3 mm \/ 4 pcs","offer_id":52421908889874,"sku":"PENGJSCS00685x4","price":8.42,"currency_code":"USD","in_stock":true},{"title":"4 mm \/ 4 pcs","offer_id":52421908922642,"sku":"PENGJSCS00687x4","price":8.42,"currency_code":"USD","in_stock":true},{"title":"6 mm \/ 4 pcs","offer_id":52421908955410,"sku":"PENGJSCS00686x4","price":8.83,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture1of5_2ce4a4c6-1c5e-4f65-b1f9-fe483cabb64f.jpg?v=1783349172","url":"https:\/\/homediyer.com\/products\/flexible-coupling-coupler-connector-3mm-4mm-6mm-bore","provider":"HomeDIYer","version":"1.0","type":"link"}