Safety and security lock nuts "U-NUT" and "FINE U-NUT" are available in a variety of sizes and shapes.
"U-NUT" and "FINE U-NUT" are adopted in various medical devices such as wheelchairs and digital panorama X-ray imaging equipment. "U-NUT" is a locking nut that is active in various industries ranging from cars, motorcycles, and industrial machinery to steel structures like railways and bridges. "FINE U-NUT" is a locking nut specifically for bearings used in rotating shafts of industrial machinery such as ball screws and spindles. We offer a rich lineup including the reliable locking nut "U-NUT" that ensures secure fastening, and the bearing locking nut "FINE U-NUT" that eliminates the need for traditional keyway machining of shafts and the installation of toothed washers. We also have the precision lock nut "TWIN FU-NUT," which further enhances the locking performance of FINE U-NUT with two friction rings. We also accept orders for custom shapes. 【Product Lineup】 ■U-NUT ■FINE U-NUT ■TWIN FU-NUT *For more details, please refer to the PDF materials or feel free to contact us. *3D CAD data is also available for download.
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basic information
"Metal Ring Loosening Prevention Function" Structure: The "U-NUT" and "FINE U-NUT" consist of two parts: the nut body and a friction ring (special spring), with the friction ring integrated into the top surface of the nut through a riveting process. Function: The force generated by the elasticity of the friction ring, along with the force that pushes against the male thread flank, creates a pre-torque (friction torque) that exhibits the loosening prevention effect.
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Applications/Examples of results
【Delivery Examples (Excerpt)】 ＜U-NUT＞ ■ Bridge Collapse Prevention Device ■ Marine Engine ■ Motorcycle Rear Suspension ＜FINE U-NUT＞ ■ Semiconductor Automatic Sealing Device ■ Ball Screw ■ Food Machinery ＜TWIN FU-NUT＞ ■ Automatic Segiri Processing Machine ■ Sugarcane Harvester *For more details, please refer to the PDF materials or feel free to contact us.
catalog（2）
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CAD data（64）
| Model number | overview | File |
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| FUN_SUS | sldpr data |
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| FUN_SS | sldpr data |
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| FUN_SC | sldpr data |
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| FUN_SUS | IGS data |
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| FUN_SS | IGS data |
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| FUN_SC | IGS data |
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| CU_SUS | sldprt data |
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| CU_SS_Molten Zinc Coating | IGS data |
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| U_SC | IGS data |
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| U_SC | sldprt data |
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| BLU_SUS | IGS data |
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| BLU_SUS | sldprt data |
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| GU_SS | IGS data |
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| GU_SS | sldprt data |
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| SU_SUS | IGS data |
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| SU_SUS | sldprt data |
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| TFU_SC | sldprt data |
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| TFU_SC | IGS data |
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| WU_SC | sldprt data |
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| WU_SC | IGS data |
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| WU_SS | sldprt data |
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| WU_SS | IGS data |
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| WU_SUS | sldprt data |
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| U_SS | IGS data |
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| U_SS | sldprt data |
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| U_SUS | IGS data |
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| U_SUS | sldprt data |
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| U_3 types_SC | sldprt data |
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| U_3 types_SC | IGS data |
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| U_3 types_SS | sldprt data |
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| U_3 types_SS | IGS data |
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| U_3 types_SUS | sldprt data |
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| U_3 types_SUS | IGS data |
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| FLANGE_SUS | IGS data |
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| UNC_SC | sldprt data |
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| UNC_SC | IGS data |
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| UNC_SS | sldprt data |
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| UNC_SS | IGS data |
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| WU_SUS | IGS data |
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| WELD_SS | sldprt data |
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| WELD_SS | IGS data |
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| CAP_SS | sldprt data |
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| CAP_SS | IGS data |
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| CAP_SUS | sldprt data |
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| CAP_SUS | IGS data |
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| FLANGE_SC | sldprt data |
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| FLANGE_SC | IGS data |
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| FLANGE_SUS | sldprt data |
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| Small U_SC | sldprt data |
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| Small U_SC | IGS data |
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| Small U_SS | sldprt data |
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| Small U_SS | IGS data |
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| Small U_SUS | sldprt data |
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| CU_SS_Molten Zinc Coating | sldprt data |
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| CU_SUS | IGS data |
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| FLANGE_SS | sldprt data |
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| FLANGE_SS | IGS data |
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| UNC_SUS | sldprt data |
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| UNC_SUS | IGS data |
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| Seat cushion with attachment_SS | sldprt data |
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| Seat cushion with payment_SS | IGS data |
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| Seat with metal base_SUS | sldprt data |
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| Seat with metal base_SUS | IGS data |
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| Small U_SUS | IGS data |
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Company information
Since our establishment in 1962, Fuji Precision has focused exclusively on the research and development of locking nuts, growing into a comprehensive manufacturer of locking nuts. The 'U-Nut' brand was the first in the industry to introduce the "metal ring locking function" to bolts and nuts, which were traditionally considered prone to loosening. This groundbreaking product received a significant response upon its release and has now grown to capture a 50% share of the domestic market, becoming synonymous with locking nuts. Although bolts and nuts may be considered small parts, they play a crucial role in connecting functions and technologies. They can be described as cross-point technology that combines cutting-edge technologies and opens up new technological fields. Fuji Precision regards this theme as an eternal proposition and has been committed to product development that anticipates the needs of the times, while pursuing high quality and high added value in our products. Our future goal is to become the world's number one comprehensive manufacturer of locking nuts. We will continue to strive to create products that meet your trust and contribute to the industrial sector and society.