Helicoil Stainless Steel Screw Thread Inserts
HeliCoil Screw Thread Inserts
Helicoil Screw Thread Inserts Logo
The HeliCoil Thread Insert System
HeliCoil Screw Thread Inserts are helically wound, precision formed coils of extremely hard stainless steel (18-8) diamond shaped wire. 
When installed into a HeliCoil tapped hole, the HeliCoil insert provides permanent conventional screw threads. 

HeliCoil screw thread inserts have a driving “tang” for installation which is notched for easy removal.
HeliCoil Materials & Platings
HeliCoil Insert Materials

Besides the standard 304 (18-8) stainless steel, HeliCoil 
screw thread inserts are also available in:

• Inconel X-750
• Nimonic 90
• Phosphor Bronze
• Nitronic 60
• Titanium

HeliCoil Insert Platings

• Dry Film Lubricant (Mollylube)
• Cadmium Plating
• Zinc Plating
• Silver Plating
• Primer Free (Heli-Guard)
HeliCoil Insert Lengths
HeliCoil helical inserts are available in lengths from 1 to 3 times the nominal diameter of the bolt or screw.
Helicoil Inconel X-750 Screw Thread Inserts
Helicoil Free Running Screw Thread Inserts
HeliCoil Insert Sizes
HeliCoil Screw Thread Inserts are available in:

•Metric (Coarse & Fine)
Whitworth (BSW, BSF, BSPF, BA)
Unified Thread (UNC & UNF)
Spark Plug 
Pipe Thread
HeliCoil TwinSerts
About HeliCoil TwinSerts
HeliCoil TwinSerts restore damaged holes to the original thread size. They are used for salvaging incorrectly 
tapped holes and holes that are stripped, off-centre, or damaged. 

HeliCoil TwinSerts should be used when the oversize condition of the hole is beyond the corrective range of 
HeliCoil OverSize Inserts. 

As the name implies, a HeliCoil TwinSert consists of two HeliCoil inserts - a HeliCoil TwinSert Outer Insert, and 
an Inner Insert. The Outer HeliCoil TwinSert Insert is always free running while the Inner HeliCoil TwinSert Insert 
can be either free running or screw-locking. 

HeliCoil TwinSerts are available in numerous nominal thread sizes. 
HeliCoil Free Running Inserts 

The standard HeliCoil helically wound insert with precision-formed rounded coils and a diamond 
shaped cross-section. When installed, they provide the hole with smooth free running threads. 
Helicoil Screw Lock Screw Thread Inserts
HeliCoil Screw-Lock Inserts 

HeliCoil Screw Lock Inserts have all the characteristics of free running inserts but in addition, 
one or more coils in the middle of the screw lock insert are polygon shaped. These coils serve 
as a locking device by gripping the threads of the installed screw, effectively preventing the 
screw from loosening under vibration or impact.

HeliCoil Screw Lock Inserts permit frequent removal and reassembly of bolts without appreciable 
loss of torque. They positively secure the screw against loosening caused by vibration and shock 
and they will not relax their grip on the screw even in tough metals such as cast iron, alloy steel, 
titanium etc. 
Helicoil Titanium Screw Thread Inserts
Helicoil Phosphor Bronze Screw Thread Inserts
Helicoil Twinserts
Bollhoff HeliCoil Germany
Armstrong Precision Components UK

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Products 

• Screw Thread Inserts
> HeliCoil 
> ArmaCoil
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> Screw Thread Insert Taps
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