Welcome to Helicoil.co.za

HELICOIL® thread inserts have been proven in practice. For over 65 years. They are available in Free Running and Screwlock versions. The green or red colour simplifies identification when installed.

The HELICOIL® is used in mechanical engineering, electronics, automotive and aerospace industries. HELICOIL® is also applied in gear housings, exhaust systems, engines and satellites, thread reinforcement, repeated installations, maintenance and repair as well as in lights, electrical appliances, hammer drills and printing presses.

HELICOIL® Plus thread inserts comply with a variety of requirements and industry standards, including those in the aerospace industry, and feature other approvals as well as suitability tests, e.g. in the field of power plant technology.

Features & Benefits of Helicoils


Heli-Coil inserts provide a positive means for protecting and strengthening
tapped threads in any material. The unique design features of the insert offer
many benefits.

Stronger Assemblies
Tapped threads are strengthened because the inherent flexibility of the insert provides
a more balanced distribution of dynamic and static loads throughout the length of thread
engagement. This flexibility also compensates for variation in lead and angle error allowing each coil to carry its share of the load.

No Thread Wear
Thread life is dramatically increased even after repeated assembly and disassembly
because the insert hardness and surface finish practically eliminate erosion of the
thread form due to frictional wear.

Corrosion Resistance
Under normal environmental conditions, Heli-Coil inserts minimize galvanic action within
the threaded assembly because of their superior corrosion resistance.

Design Flexibility
Bolt tensile strength can be balanced against parent material shear strength, assuring
bolt failure rather than parent material damage. Five insert lengths are available in each
thread size.

Eliminate Stress
Virtually no stress is introduced into the parent material because there is no staking,
locking, swaging or keying in place – the outward spring-like action of the insert
holds it in place.

Minimize Space & Weight
Heli-Coil inserts allow the use of smaller bosses and flanges than any other insert.
Heli-Coil inserts can generally be incorporated into existing designs, where no other
provision has been made for an insert, without increasing boss size.

Minimize Total Cost
Cost savings abound. Lower insert cost, lower installation cost and Heli-Coil inserts provide design flexibility by allowing a wide choice of parent materials while maintaining maximum threaded assembly strength.

True Clamping Torque
Maximum clamping action and bolt tension are assured with minimum wrench torque
because of the mirror-smooth surface finish of Heli-Coil inserts.

Wide Temperature Range
Heli-Coil stainless steel inserts can be used in temperatures ranging from -320°F to +800°F.

Quality & Reliability
Stringent Quality Assurance and Engineering Standards are rigidly enforced in all phases
of the manufacturing process. This assures integrity of your product design.

Screw Locking INserts

Heli-Coil offers three types of Locking Inserts for multiple applications.

Screw-Locking Inserts


  • A resilient locking mechanism that grips the bolt and prevents it from loosening under vibration or impact.
  • Repeated assembly and disassembly without appreciable loss of positive self-locking torque.
  • Savings in space, weight and money, through the elimination of lock wiring, lock nuts, lock washers, chemical compounds, plastic pellets/patches and/or other locking mechanisms.
  • Inch inserts dyed red for easy identification.
  • Meets NASM8846, MA1565, NASM21209, MA3329, MA3330, MA3331.

Hi-Torque Inserts


  • Similar to Screw-Locking but with higher prevailing torque which compensates for reduced friction in highly lubricated applications.
  • Ideal for higher vibration applications.
  • Approximate 40% increase in prevailing torque levels.
  • Available in #10 through 3/8″ UNF only.
  •  Meets AS1394, AS3094, AS3095, AS3096, AS3097

Stud-Lock Inserts


  •  Highest prevailing torque insert available.
  • Enables use of threaded rod for space-saving stud applications.
  • Allows for any class fit of threaded rod.
  • Eliminates inconsistencies caused by interference-fit studs.
  • Available for both straight and step studs, #10 through 1/2″ UNC and UNF.
  • Meets AS1229, AS3080, AS3081, AS3082, AS3083.