Thread inserts for metals

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For high-strength fastenings

HELICOIL® thread inserts create high-strength fastenings in metal low-strength materials and have been well established on the market for more than 60 years.



HELICOIL® plus thread inserts

HELICOIL® plus thread inserts create high-strength, wear-resistant, heat-resistant threads of highest precision. They are available in free running and screwlock version. The green or red colour allows easier identification when they are installed.


  • Corrosion and heat-resistant
  • Wear-free
  • Rejects recovery
  • Uniform load and stress distribution
  • Easy identification even when installed (thanks to colouring)
  • Available in different variants for the most different requirements
  • Assembly systems, tools, and products available from one source

HELICOIL® thread inserts are available with imperial or metric dimensions and as special designs.


The newest generation of this technology is HELICOIL® plus. Easy handling
allows easier installation. Thanks to the reduced diameter in the first thread, the thread insert can be screwed in like a screw.

HELICOIL® plus inserts are highly wear-, corrosion-, and heat-resistant and show low thread friction within small tolerances.

Böllhoff is certified

HELICOIL® plus thread inserts comply with many common industry requirements and standards.

Certificates & standards

Product types



HELICOIL® plus free running and HELICOIL® plus screwlock threaded inserts

The thread insert with precision formed, rhombic profile is available as free running or screwlock version.

Our seal of quality, a rhombic imprint at the end of the last thread, unmistakably identifies each Böllhoff HELICOIL® plus thread insert as an original.

HELICOIL® tangfree

HELICOIL® tangfree

HELICOIL® tangfree threaded insert

No tang break and no tang removal. No tang is required for the installation of HELICOIL® tangfree coil thread. Therefore the coil thread can installed on both sides without loss of quality.
HELICOIL® tangfree: The up-to-date HELICOIL® coil thread insert technology.

HELICOIL® tangfree is compatible to the HELICOIL® plus system

This means:

  • Identical HELICOIL® plus holding threads
  • No design modification
  • No other taps necessary

tangfree® is a registered trademark of the Böllhoff Company.




Is the tapped hole widely torn?
Has the thread been cut too large?

For these cases the HELICOIL® plus TWINSERT is the ideal repair element.

HELICOIL® plus TWINSERT consists of two HELICOIL® plus thread inserts. The external element is a HELICOIL® plus free running. For the internal insert you can choose between HELICOIL® plus free running and HELICOIL® plus screwlock.

Free running version

Free running version

HELICOIL® free running

Every winding of the thread insert with precision formed, rhombic profile is free running. The result is an internal thread true to gauge that can be used on both sided.

Thanks to its green colour, the HELICOIL® plus free running is easier to identify after its installation.

It is conforming to DIN 8140-a.

Screwlock version

Screwlock version

HELICOIL® screwlock

The HELICOIL® plus screwlock has the same benefits regarding the threads as the HELICOIL® plus free running and it is confirming to DIN 8140-b.

Additionally an integrated screw clamping area serves as a screw-lock.

The screw clamping is realised by one or more polygone formed windings that clamp the flanks of the screwed-in screws. The result is an elastic frictional resistance.

The HELICOIL® plus screwlock can be recognised thanks to its red colour.
The HELICOIL® screwlock inserts can only be used with screws of property class 8.8 or higher.


  • HELICOIL® application

    Automotive & aerospace

    Car gear box cover made of aluminium die-cast,
    HELICOIL® plus, M 14 x 1,5 x 14, free running

    For use in gear boxes, exhaust systems, engines and satellites, for thread reinforcement, repeated screwing, maintenance and repair

  • HELICOIL® application

    Electronics, sheet metal, plastic

    Carrier plate for electronic components made of aluminium pressure die-casting

    For use in lamps, electrical appliances, drill hammers, etc.

  • HELICOIL® application

    Machines and plants

    Machine construction console ,
    Material G-AISi9 Mg,
    HELICOIL® plus, M 8 x 12,
    free running

    For use in printing presses, in high temperature range, for repeated screwings, maintenance and repair

Product catalogues

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Böllhoff is certified

Here, you find out in which fields!

Certificates & standards


You need any product information or support?


HELICOIL® free running – thread insert

HELICOIL® screwlock – thread insert

HELICOIL® tangfree – thread insert

HELICOIL® Tangfree Screwlock – thread insert


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