"U-NUT" that supports safety, reliability, and productivity in the mobility sector.
Registered with manufacturer standards, from specification consultation to testing support. We provide stable quality and meet customer needs.
The "U-NUT" locking nut has been adopted by four major domestic motorcycle manufacturers, primarily for two-wheeled vehicles, and is also used in four-wheeled vehicles for engine mounts and securing onboard components. Additionally, the "FINE U-NUT" for bearings has a proven track record in automotive manufacturing robots. As a comprehensive manufacturer of locking nuts, we support safety, reliability, and productivity in the mobility sector. In addition to the high locking performance of our products, we consistently pursue higher safety and reliability through stable quality based on manufacturer standards, product proposals tailored to specific applications, consultations on specifications based on existing products, and testing support. ▼ U-NUT Registered Standards (for Mobility) TMS Standard (Toyota), HES Standard (Honda), KES Standard (Kawasaki Motors), SES Standard (Suzuki), YGK Standard (Yamaha Motor), KYB Standard (Kayaba) ▼ Product Proposals Based on Applications such as Weight Reduction, High Strength, and Corrosion Resistance Lightweight: Compact, low-profile, and titanium options that are lighter than standard sizes High Strength: High-strength products (equivalent to 8N) that have undergone forging and heat treatment, SCM435 products Corrosion Resistance: Electroplated and SUS products, etc.
basic information
【Exhibiting at Nagoya Automotive!】 Fuji Precision Booth: Hall D N8-45 Dates: November 25 (Wednesday) - November 27 (Friday), 2026 Venue: Aichi Sky Expo (Aichi Prefectural International Exhibition Center) Halls C-F 【U-NUT/FINE U-NUT Specifications】 A product in which a friction ring (special spring) is fixed and integrated onto the top surface of the nut body through riveting. The force generated by the elasticity of the friction ring and the force pressing against the male thread flank create a pre-torque (friction torque), which exhibits a loosening prevention effect. ▼ U-NUT Features - Fastening Function: Provides stable loosening prevention effect - Drop Prevention: Prevents synchronous drop even if axial force decreases - Reusability: Can be reused - Standalone Component: Exhibits loosening prevention effect on its own, allowing for a reduction in the number of parts - Heat and Cold Resistance: Excellent heat and cold resistance due to being an all-metal product ▼ FINE U-NUT Features - Balance: Improves rotational balance of shafts and bearings - Weight Reduction: Allows for the use of thin-walled hollow shafts - Cost Reduction: Achieves total cost reduction as key grooves for the shaft and washer are unnecessary
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Model number/Brand name
「U-NUT」「FINE U-NUT」
Applications/Examples of results
■U-NUT - Two-wheeled Side stand, engine hanger, sprocket, rear axle, rear arm, muffler bracket - Four-wheeled Engine mount, spring adjustment fixture, etc. Additionally, widely adopted in special vehicles, construction machinery, agricultural equipment, transport machinery, railways, infrastructure, construction, and other fields. ■FINE U-NUT Welding robots, assembly robots Additionally, used in semiconductor cleaning equipment, food machinery, medical devices, commercial blowers, NC rotary tables, and many other machine tools and industrial machinery.
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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.