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Product Lineup*Dimensional charts and tightening torque charts can be found here.

FUJILOK U-NUT

The first name in locknuts

The FUJILOK U-NUT introduced the industry's first "Metal ring locking function". They're actively used in all industries in everything from steel structures such as railways and connecting bridges to cars, motorcycles and industrial machinery.
FUJILOK U-NUT
introduction video
  • FUJILOK U-NUT

    The FUJILOK U-NUT has built up a record of trust and excellent performance since its creation over 50 years ago
  • GU-NUT

    A locknut that conforms to JIS standards
  • SU-NUT

    FUJILOK U-NUT + theft/tamper prevention
  • FSW U-NUT

    An integrated the FUJILOK U-NUT and washer unit

FINE U-NUT

A revolution in bearing fastening

A locknut for use with bearings that eliminates the need to machine keyways on shafts and the installation of toothed lock washers. It also improves the rotational balance of bearings in all machine industries.
FINE U-NUT
introduction video
  • FINE U-NUT

    A locknut for use with bearings
  • FINE U-NUT TOOL

    A tightening tool made especially for the FINE U-NUT
    ・FUN TOOLSET 00-10
    ・FINE U-NUT tightening sockets and handles 11-20

TWIN FU-NUT

A prevailing-torque-type precision locknut

The industry's first prevailing-torque-type precision locknut. It uses two friction rings to further enhance the locking performance of the FINE U-NUT.
TWIN FU-NUT
introduction video
  • TWIN FU-NUT

    A prevailing-torque-type precision locknut

Special products

For customer requests that cannot be fulfilled with off-the-shelf products

Regardless of whether it is a custom order or a full order, if you have a request that cannot be fulfilled with an off-the-shelf product, please do not hesitate to contact us.
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  • Special products

    We can manufacture products with special shapes and materials!

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Structure & Function

FUJILOK U-NUT

The FUJILOK U-NUT introduced the industry's first "Metal ring locking function".
The FUJILOK U-NUT sparked a revolution in the area of bolts and nuts where up until that point loosening had been considered unavoidable.
since its creation over 50 years ago.
The FUJILOK U-NUT is now highly regarded as the first name in locknuts across all industries from steel structures such as railways and connecting bridges to automobiles, motorcycles, and on up to industrial machines.

The industry's first [Metal ring locking function]

The FUJILOK U-NUT consists of a nut and friction ring (specialized ring).
The friction ring is secured to and integrated with the top face of the nut by crimping.

[Locking effect] created by the friction ring

When the FUJILOK U-NUT is tightened onto the bolt, the friction ring comes into contact with the thread portion of the bolt.
As the nut is tightened further, the friction ring begins to bend along with the screw thread and presses against the shaft screw threads.
A spring effect produced by the friction ring (P), along with a reactionary force that pushes against the screw flank surface (P'), generates prevailing torque (frictional torque) and demonstrates the locking function.

1.Tighten in the same way as an ordinary nut. 2.The friction ring touches the bolt thread. 3.Prevailing torque is genarated. Fastening is completed.

FUJILOK U-NUT

"FINE U-NUT" can be positioned arbitrarily and appropriately regardless of whether it is a toothed washer, and torque management is easy. An epoch-making lock nut for bearings that does not require shaft keyway machining or toothed washer mounting technology. It improves the rotational balance of bearings that generate the "force" of all industrial machinery. In addition, we have achieved a reduction in equipment rotation loss and a reduction in power consumption.

[Locking effect] created by the friction ring

When "FINE U-NUT" is screwed onto a shaft, the friction ring comes into contact with the shaft thread. As the nut is tightened further, the friction ring begins to bend along with the screw thread and presses against the shaft screw threads.
A spring effect produced by the friction ring (P), along with a reactionary force that pushes against the screw flank surface (P'), generates prevailing torque (frictional torque) and demonstrates the locking function.

Reasons why FUJILOK U-NUT・FINE U-NUT is chosen

  • Fastening function

    Demonstrates stable locking function.

  • Dropout prevention

    Demonstrates stable locking function.
    Effective even at the intermediate position of the bolt

  • Reusability

    Can be reused with the function of prevailing torque

  • Simple fastening

    The FUJILOK U-NUT is easy to install, just like general nuts.

  • Simplex parts

    It demonstrates a locking effect by itself.

  • Heat and cold resistance

    An all-metal product with excellent resistant to heat and cold,and is not affected by heat.

  • Various shapes

    Various shapes are available, such as CAP type U-NUT and weld type U-NUT.

  • Variety of sizes and types

    Thread size of FUJILOK U-NUT is M3-M115, FINE U-NUT is up to M8-M150

    *Standards are Metric, Whit, and Unified
  • Special product production

    We can also manufacture special shapes upon request.

  • Cost reduction

    Machining, parts management, and fastening technology are unnecessary.

  • Balance
    (FINE U-NUT)

    Improves the rotational balance of shafts and bearings.

  • Weight reduction
    (FINE U-NUT)

    The number of parts can be reduced. It allows for the use of hollow shafts that are thinner than normal.

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