{"product_id":"lmk-square-flange-linear-bearings-3d-printer-cnc-parts","title":"LMK Square Flange Linear Bearings – 3D Printer \u0026 CNC Parts","description":"\u003ch2\u003eJARBLUE Square Flange Linear Bearings – LMK Series\u003c\/h2\u003e\n\u003cp\u003eUpgrade your 3D printer or CNC machine with these precision-engineered \u003cstrong\u003eLMK Square Flange Type Linear Bearings\u003c\/strong\u003e from JARBLUE. Designed for smooth, low-friction linear motion, these steel bearings feature a durable black oxide coating for enhanced corrosion resistance and longevity. Available in a range of sizes — LMK6UU, LMK8UU, LMK10UU, LMK12UU, LMK13UU, LMK16UU, and LMK20UU — to suit a wide variety of builds and applications.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eMade in Mainland China.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSquare Flange Design:\u003c\/strong\u003e Easy bolt-down mounting for secure, stable installation in frames and carriages\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eBlack Oxide Coating:\u003c\/strong\u003e Provides resistance to rust and wear for extended service life\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eHigh-Grade Steel Construction:\u003c\/strong\u003e Ensures precision, strength, and consistent performance under load\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCE Certified:\u003c\/strong\u003e Meets international quality and safety standards\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSurface Roughness Ra 0.4:\u003c\/strong\u003e Ultra-smooth surface finish for minimal friction and accurate linear travel\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eMultiple Size Options:\u003c\/strong\u003e Choose from 6mm, 8mm, 10mm, 12mm, 13mm, 16mm, or 20mm shaft diameters\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003ePack of 2–5 Pieces:\u003c\/strong\u003e Flexible quantity options to match your project needs\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eNo High-Concern Chemicals:\u003c\/strong\u003e Safe for use in enclosed workshop and home environments\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003ctable\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eJARBLUE\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eMaterial\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eSteel\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCoating\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eBlack Oxide\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eSurface Roughness\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eRa 0.4\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCertification\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eCE\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eModel Numbers\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eLMK6UU, LMK8UU, LMK10UU, LMK12UU, LMK13UU, LMK16UU, LMK20UU\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOrigin\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eMainland China\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\n\n\u003ch3\u003eCommon Applications\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eFDM and CoreXY 3D printer axis rails and carriages\u003c\/li\u003e\n  \u003cli\u003eCNC routers and milling machine linear guides\u003c\/li\u003e\n  \u003cli\u003eLaser cutter and engraver motion systems\u003c\/li\u003e\n  \u003cli\u003eDIY robotics, automation, and linear actuator projects\u003c\/li\u003e\n  \u003cli\u003eReprap, Prusa, and custom 3D printer builds\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Products You May Like\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/10pcs-durable-gold-blade-nut-metal-universal-trimmer-accessories-anti-loosening-line-left-hand-thread-replacement-parts-1\"\u003e10pcs Durable Gold Blade Nut Metal Universal Trimmer Accessories\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/10pcs-2-pin-quick-splice-spring-wire-connectors-lock-terminals\"\u003e10pcs 2-Pin Spring Wire Connectors – Quick Splice Lock Terminals\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/stainless-steel-self-tapping-screws-m2-2-m4-8-phillips-wood-hinge\"\u003e10PCS Stainless Steel Self-Tapping Screws M2.2–M4.8 Phillips\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.osha.gov\/eye-face-protection\" target=\"_blank\" rel=\"noopener\"\u003eOSHA on eye and face protection\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: Which shaft diameter should I choose for my 3D printer linear rail?\u003c\/h4\u003e\n\u003cp\u003eA: The most common shaft diameters for 3D printers are 8mm (LMK8UU) and 12mm (LMK12UU). LMK8UU is widely used on standard Prusa-style printers, while LMK12UU is popular on larger or heavy-duty builds. Always measure your existing smooth rod diameter before selecting a size.\u003c\/p\u003e\n\u003ch4\u003eQ: What is the difference between LMK square flange bearings and standard LM linear bearings?\u003c\/h4\u003e\n\u003cp\u003eA: LMK square flange linear bearings feature a flat, square mounting flange with four bolt holes, making them much easier to mount directly onto flat surfaces or frame panels. Standard LM bearings (cylindrical) typically require a separate pillow block housing. The square flange design simplifies assembly and provides a more rigid, stable mount.\u003c\/p\u003e\n\u003ch4\u003eQ: Are these LMK bearings compatible with standard smooth rods?\u003c\/h4\u003e\n\u003cp\u003eA: Yes. JARBLUE LMK series bearings are manufactured to standard dimensional tolerances and are compatible with any standard precision smooth rod of the matching diameter (e.g., LMK8UU fits an 8mm smooth rod). Ensure your rod surface is clean and within spec for best performance.\u003c\/p\u003e\n\u003ch4\u003eQ: How many pieces come in a pack?\u003c\/h4\u003e\n\u003cp\u003eA: This listing offers flexible pack options of 2 to 5 pieces. Please select your preferred quantity from the available options when ordering.\u003c\/p\u003e\n\u003c!-- production-packaging-notice --\u003e\n\u003ch3\u003eProduction \u0026amp; Packaging Notice\u003c\/h3\u003e\n\u003cp\u003eTo maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.\u003c\/p\u003e\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"Which shaft diameter should I choose for my 3D printer linear rail?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"The most common shaft diameters for 3D printers are 8mm (LMK8UU) and 12mm (LMK12UU). LMK8UU is widely used on standard Prusa-style printers, while LMK12UU is popular on larger or heavy-duty builds. 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