{"product_id":"ket-638-638zz-metric-miniature-ball-bearing-8x28x9mm-high-speed-precision-micro-bearing","title":"KET 638 \/ 638ZZ Metric Miniature Ball Bearing (8x28x9mm) - High-Speed Precision Micro Bearing","description":"\u003cp\u003e\u003cb\u003eProduct Description:\u003c\/b\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eCore Selling Points\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eExact Metric Specifications:\u003c\/b\u003e Precision engineered with an 8 mm inner diameter, a 28 mm outer diameter, and a 9 mm width, specifically designed for seamless integration into global metric-based mechanical assemblies.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eExtreme High-Speed Stability:\u003c\/b\u003e Capable of reaching up to 34,000 RPM with oil lubrication and 28,000 RPM with grease, ensuring flawless operational stability under rapid rotational stress.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eReliable Load Capacity:\u003c\/b\u003e Delivers a robust 4,550 N basic dynamic load rating and 1,970 N static load rating, providing excellent durability for compact high-stress micro-applications.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eFactory-Direct Supply:\u003c\/b\u003e Manufactured by Ningbo Kexiang Bearing Technology Co., Ltd. with a robust annual capacity of 100 million sets, securing highly competitive B2B wholesale pricing for global procurement.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eDetailed Overview\u003c\/b\u003e The KET 638 series deep groove ball bearing is a premium ultra-precision component belonging to our specialized Metric Miniature Series. Established in 2008 in Ningbo, Zhejiang Province, our highly automated manufacturing facility operates under the internationally registered trademark \"KET,\" supplying world-class bearings to global OEM markets. The 638 model provides the ultimate balance of a compact 8 mm shaft size and superior load-bearing capability. It delivers true-to-design dimensional exactness with every production batch for clients utilizing strict metric engineering standards.\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eExact Technical Specifications\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBrand:\u003c\/b\u003e KET\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eModel Variants:\u003c\/b\u003e 638 (Open Type) \/ 638ZZ (Shielded Type)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eInner Diameter (d):\u003c\/b\u003e 8 mm\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eOuter Diameter (D):\u003c\/b\u003e 28 mm\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eWidth \/ Thickness (B\/B1):\u003c\/b\u003e 9 mm (Open) \/ 9 mm (Shielded)\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eChamfer (r):\u003c\/b\u003e 0.3 mm\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBasic Dynamic Load Rating (Cr):\u003c\/b\u003e 4,550 N\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eBasic Static Load Rating (Cor):\u003c\/b\u003e 1,970 N\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eLimiting Speed (Grease Lubrication):\u003c\/b\u003e Up to 28,000 RPM\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eLimiting Speed (Oil Lubrication):\u003c\/b\u003e Up to 34,000 RPM\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003ePrimary Industrial Applications\u003c\/b\u003e The KET Metric Miniature Series is highly versatile and globally trusted by precision engineers. Featuring an industry-standard 8 mm bore profile with enhanced thickness, the 638 bearing is specifically ideal for:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eHigh-speed industrial micro motors, precision cooling fans, and delicate robotic actuators.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eRemote control UAVs (Drones), advanced RC models, and aerospace micro-mechanisms.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eAdvanced medical equipment, scientific testing instruments, and precision appliances enduring high operational stress.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eStrategic Manufacturing Partner Qualifications\u003c\/b\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eInternationally Certified Quality Systems:\u003c\/b\u003e We operate strictly under rigorous global quality management frameworks, proudly holding dual ISO9001 certifications and the stringent automotive industry standard IATF16949.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eRecognized Engineering Innovation:\u003c\/b\u003e Our continuous investment in engineering R\u0026amp;D is officially validated by our recognition as a High-Tech Enterprise and a Technology-Based SME in Zhejiang Province.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eGlobal Material Safety Compliance:\u003c\/b\u003e We exclusively utilize premium raw materials that meet strict international safety directives. Our products pass comprehensive third-party SGS laboratory testing for SVHC and RoHS compliance.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cb\u003eUncompromised Quality Control:\u003c\/b\u003e 100% precision-tested utilizing state-of-the-art roundness instruments and automatic noise testing equipment prior to global shipment.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cb\u003eContact Us for Global Wholesale \u0026amp; Bulk Purchasing\u003c\/b\u003e Optimize your supply chain costs without compromising on extreme speed and load performance. Contact our international business development department today for B2B quotes, comprehensive technical datasheets, or to request free evaluation samples.\u003cb\u003e\u003c\/b\u003e\u003c\/p\u003e","brand":"KET Precision Bearings","offers":[{"title":"8mm \/ 28mm \/ 2.5 mm (Open) \/ 3 mm (Shielded)","offer_id":49420851118336,"sku":null,"price":0.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0829\/6890\/3936\/files\/Ultra-microprecisiondeepgrooveballbearing.webp?v=1787508371","url":"https:\/\/ketprecisionbearings.com\/ru\/products\/ket-638-638zz-metric-miniature-ball-bearing-8x28x9mm-high-speed-precision-micro-bearing","provider":"KET Precision Bearings","version":"1.0","type":"link"}