{"product_id":"universal-flexible-shaft-coupling-coupler-motor-u-joint-connector-rc-boat-steel","title":"Universal Flexible Shaft Coupling Coupler Motor U Joint Connector RC Boat Steel","description":"\u003cdiv class=\"hdiy-desc\"\u003e\n\u003cdiv class=\"hdiy-overview\"\u003e\n\u003ch2\u003eUniversal Flexible Shaft Coupling Coupler — Precision Motor Connection for RC Boats \u0026amp; DIY Drives\u003c\/h2\u003e\n\u003cp\u003eWhen misalignment between motor and drive shaft causes vibration, noise, or premature wear, the right universal flexible shaft coupling coupler makes all the difference. Designed for RC boat builders, robotics enthusiasts, and mechanical DIYers who need reliable torque transmission across slight angular or parallel offsets, this U-joint connector eliminates the frustration of rigid couplings that crack under load.\u003c\/p\u003e\n\u003cp\u003eEach coupler is machined from steel and features a flexible universal joint design. Inner diameter (I.D.) options range from 6 mm to 20 mm (approx. 0.24″–0.79″), outer diameter (O.D.) from 16 mm to 32 mm (approx. 0.63″–1.26″), and overall length from 42 mm to 85 mm (approx. 1.65″–3.35″). Set screws secure the coupler firmly to both shafts. Available in 1PCS or 2PCS packing quantities.\u003c\/p\u003e\n\u003cp\u003eTypical applications include RC boat motor-to-propeller shaft connections, small CNC machine spindle couplings, DIY electric vehicle drive trains, and benchtop lathe or drill press shaft adapters — anywhere a flexible shaft coupling for motor is needed to absorb minor misalignment without sacrificing torque.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-compat\"\u003e\n\u003cspan class=\"hdiy-compat-icon\"\u003e⚙️\u003c\/span\u003e \u003cstrong\u003eCompatibility:\u003c\/strong\u003e Fits standard round motor shafts and drive shafts matching the selected I.D. Verify your shaft diameter before ordering. Set screw secures to both ends.\u003c\/div\u003e\n\u003cdiv class=\"hdiy-features\"\u003e\n\u003ch2\u003e✅ Key Features of These Universal 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 \u003cstrong\u003eSteel Construction\u003c\/strong\u003e — Machined steel body delivers the rigidity and durability needed for continuous rotational loads in RC boats, motors, and mechanical drives.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔄\u003c\/span\u003e \u003cstrong\u003eUniversal Joint (U-Joint) Flexibility\u003c\/strong\u003e — Accommodates slight angular and parallel shaft misalignment, reducing vibration transmission and protecting motor bearings from side-load stress.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📐\u003c\/span\u003e \u003cstrong\u003eWide Size Range\u003c\/strong\u003e — Available in 11 I.D. × O.D. × Length combinations from 6×16×42 mm up to 20×32×85 mm, covering the most common RC and DIY motor shaft diameters.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e🔧\u003c\/span\u003e \u003cstrong\u003eSet Screw Locking\u003c\/strong\u003e — Integrated set screw(s) on each end clamp securely to the shaft without adhesive, allowing tool-free repositioning and re-use.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e⚖️\u003c\/span\u003e \u003cstrong\u003eCompact \u0026amp; Lightweight\u003c\/strong\u003e — Slim O.D. profile (16–32 mm) keeps rotating mass low, important for RC boat speed performance and responsive motor control.\u003c\/div\u003e\n\u003cdiv\u003e\n\u003cspan class=\"hdiy-icon\"\u003e📦\u003c\/span\u003e \u003cstrong\u003eFlexible Pack Quantities\u003c\/strong\u003e — Choose 1PCS for a single replacement or 2PCS for a spare-ready workshop stock, with quantity pricing reflected in the variant selector.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\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\u003eProduct Type\u003c\/th\u003e\n\u003ctd\u003eUniversal Flexible Shaft Coupling \/ U-Joint Coupler\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMaterial\u003c\/th\u003e\n\u003ctd\u003eSteel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eInner Diameter (I.D.) Range\u003c\/th\u003e\n\u003ctd\u003e6 mm – 20 mm (0.24″ – 0.79″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eOuter Diameter (O.D.) Range\u003c\/th\u003e\n\u003ctd\u003e16 mm – 32 mm (0.63″ – 1.26″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eLength Range\u003c\/th\u003e\n\u003ctd\u003e42 mm – 85 mm (1.65″ – 3.35″)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eAvailable Sizes (I.D. × O.D. × L)\u003c\/th\u003e\n\u003ctd\u003e6×16×42 \/ 8×16×42 \/ 10×20×45 \/ 12×24×51 \/ 12×25×56 \/ 14×28×60 \/ 14×28×70 \/ 15×32×85 \/ 16×32×85 \/ 18×32×85 \/ 20×32×85 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eShaft Fixing Method\u003c\/th\u003e\n\u003ctd\u003eSet screw (both ends)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003ePacking Quantity\u003c\/th\u003e\n\u003ctd\u003e1PCS or 2PCS (see variant options)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eFinish\u003c\/th\u003e\n\u003ctd\u003eSee variant options\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMax Recommended RPM\u003c\/th\u003e\n\u003ctd\u003eContact us to confirm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMax Torque Rating\u003c\/th\u003e\n\u003ctd\u003eContact us to confirm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eApplication\u003c\/th\u003e\n\u003ctd\u003eRC boats, motors, CNC spindles, DIY drive systems\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-faq\"\u003e\n\u003ch2\u003e❓ Frequently Asked Questions\u003c\/h2\u003e\n\u003cdetails\u003e\n\u003csummary\u003eHow do I choose the right coupler size?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eMeasure the outer diameter of both shafts you need to connect — this is your required I.D. (inner diameter). Then select the variant whose I.D. matches your shaft size. For example, if your motor shaft is 8 mm and your drive shaft is also 8 mm, choose the 8×16×42 mm variant. If the two shafts differ in diameter, this coupler is not suitable — you would need a reducing coupler instead.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan this coupler handle angular misalignment between the motor and drive shaft?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eYes. The universal joint (U-joint) design allows for a small degree of angular misalignment — typically up to a few degrees — between the input and output shafts. This makes it well-suited for RC boat installations where the motor and propeller shaft are not perfectly in line. For large misalignment angles, a dedicated CV joint or flexible jaw coupler may be more appropriate.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eIs this coupler strong enough for RC boat use at high RPM?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThe steel construction provides solid torque transmission for typical RC boat motor outputs. However, maximum RPM and torque ratings depend on the specific size selected and the operating conditions. For high-performance or competition RC applications, please contact us to confirm suitability before ordering.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWill this coupler rust or corrode in a marine (wet) environment?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eThe coupler is made from steel. While steel offers good mechanical strength, it can be susceptible to surface oxidation in prolonged wet or saltwater environments. For RC boat use, we recommend applying a light coat of waterproof grease or corrosion inhibitor to the coupler after installation, and rinsing with fresh water after saltwater use.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eDo I need any special tools to install this coupler?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eInstallation requires only a hex key (Allen wrench) to tighten the set screws on each end of the coupler. Slide the coupler onto both shafts, align to your desired position, then tighten the set screws firmly. No adhesive, press-fit tools, or special equipment are needed for standard installations.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eWhat is the difference between the 1PCS and 2PCS packing options?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eBoth options contain the same coupler in the same size. The 1PCS option is ideal if you need a single replacement or are testing a size for the first time. The 2PCS option provides a spare unit at a better per-piece value — useful for workshop stock, multi-boat builds, or projects where having a backup on hand saves downtime.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n\u003csummary\u003eCan I use this coupler to connect two shafts of different diameters?\u003c\/summary\u003e\n\u003cdiv class=\"hdiy-faq-body\"\u003e\n\u003cp\u003eNo — this coupler has the same I.D. on both ends, so it is designed for shafts of equal diameter. If you need to connect shafts of different diameters, please contact us or browse our range of reducing shaft couplers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/details\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"hdiy-cta\"\u003e🛒 Select your coupler size (I.D × O.D × Length) and packing quantity above, then add to cart.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"HomeDIYer","offers":[{"title":"6 x 16 x 42 mm \/ 1PCS","offer_id":52421851742482,"sku":"GYJLTSHXJZC3495x1","price":4.47,"currency_code":"USD","in_stock":true},{"title":"8 x 16 x 42 mm \/ 1PCS","offer_id":52421851775250,"sku":"GYJLTSHXJZC3496x1","price":6.01,"currency_code":"USD","in_stock":true},{"title":"10 x 20 x 45 mm \/ 1PCS","offer_id":52421851808018,"sku":"GYJLTSHXJZC3497x1","price":7.21,"currency_code":"USD","in_stock":true},{"title":"12 x 24 x 51 mm \/ 1PCS","offer_id":52421851840786,"sku":"GYJLTSHXJZC3498x1","price":9.6,"currency_code":"USD","in_stock":true},{"title":"12 x 25 x 56 mm \/ 1PCS","offer_id":52421851873554,"sku":"GYJLTSHXJZC3500x1","price":11.83,"currency_code":"USD","in_stock":true},{"title":"14 x 28 x 60 mm \/ 1PCS","offer_id":52421851906322,"sku":"GYJLTSHXJZC3501x1","price":14.05,"currency_code":"USD","in_stock":true},{"title":"14 x 28 x 70 mm \/ 1PCS","offer_id":52421851939090,"sku":"GYJLTSHXJZC3503x1","price":15.53,"currency_code":"USD","in_stock":true},{"title":"15 x 32 x 85 mm \/ 1PCS","offer_id":52421851971858,"sku":"GYJLTSHXJZC3505x1","price":21.53,"currency_code":"USD","in_stock":true},{"title":"16 x 32 x 85 mm \/ 1PCS","offer_id":52421852004626,"sku":"GYJLTSHXJZC3507x1","price":21.18,"currency_code":"USD","in_stock":true},{"title":"18 x 32 x 85 mm \/ 1PCS","offer_id":52421852037394,"sku":"GYJLTSHXJZC3509x1","price":20.62,"currency_code":"USD","in_stock":true},{"title":"20 x 32 x 85 mm \/ 1PCS","offer_id":52421852070162,"sku":"GYJLTSHXJZC3511x1","price":19.87,"currency_code":"USD","in_stock":true},{"title":"6 x 16 x 42 mm \/ 2PCS","offer_id":52421852102930,"sku":"GYJLTSHXJZC3495x2","price":10.44,"currency_code":"USD","in_stock":true},{"title":"8 x 16 x 42 mm \/ 2PCS","offer_id":52421852135698,"sku":"GYJLTSHXJZC3496x2","price":11.26,"currency_code":"USD","in_stock":true},{"title":"10 x 20 x 45 mm \/ 2PCS","offer_id":52421852168466,"sku":"GYJLTSHXJZC3497x2","price":14.96,"currency_code":"USD","in_stock":true},{"title":"12 x 24 x 51 mm \/ 2PCS","offer_id":52421852201234,"sku":"GYJLTSHXJZC3498x2","price":18.35,"currency_code":"USD","in_stock":true},{"title":"12 x 25 x 56 mm \/ 2PCS","offer_id":52421852234002,"sku":"GYJLTSHXJZC3500x2","price":22.82,"currency_code":"USD","in_stock":true},{"title":"14 x 28 x 60 mm \/ 2PCS","offer_id":52421852266770,"sku":"GYJLTSHXJZC3501x2","price":27.24,"currency_code":"USD","in_stock":true},{"title":"14 x 28 x 70 mm \/ 2PCS","offer_id":52421852299538,"sku":"GYJLTSHXJZC3503x2","price":30.19,"currency_code":"USD","in_stock":true},{"title":"15 x 32 x 85 mm \/ 2PCS","offer_id":52421852332306,"sku":"GYJLTSHXJZC3505x2","price":42.2,"currency_code":"USD","in_stock":true},{"title":"16 x 32 x 85 mm \/ 2PCS","offer_id":52421852365074,"sku":"GYJLTSHXJZC3507x2","price":41.47,"currency_code":"USD","in_stock":true},{"title":"18 x 32 x 85 mm \/ 2PCS","offer_id":52421852397842,"sku":"GYJLTSHXJZC3509x2","price":40.36,"currency_code":"USD","in_stock":true},{"title":"20 x 32 x 85 mm \/ 2PCS","offer_id":52421852430610,"sku":"GYJLTSHXJZC3511x2","price":38.88,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0884\/8936\/1682\/files\/Picture4of8_a39d9490-b031-4277-9eab-6e296c5565d5.jpg?v=1783335103","url":"https:\/\/homediyer.com\/products\/universal-flexible-shaft-coupling-coupler-motor-u-joint-connector-rc-boat-steel","provider":"HomeDIYer","version":"1.0","type":"link"}