Aerospace CoilThread Inserts
Helicoil-Type Screw Thread Inserts for Repair, Reinforcement and OEM Production
GLE is an authorized distributor of KATO Perma-Coil CoilThread Inserts — the trusted helical wire thread insert solution used for aerospace, defence, industrial and MRO applications.
Why aerospace buyers specify them
- • Restores worn, stripped or damaged internal threads
- • Reinforces aluminum, magnesium and titanium components
- • Delivers hardened wear resistance without oversized bushings
- • Available in free-running and self-locking styles
What is a CoilThread or Helicoil-type insert?
A CoilThread insert is a precision-formed helical coil of stainless steel or alloy wire installed into a tapped hole to restore or reinforce internal threads. It is widely used in aerospace and defence repair, OEM production and MRO operations.
GLE supplies KATO Perma-Coil inserts in both free-running and self-locking versions, with inch and metric sizes available and cross-referenced to military and aerospace specifications such as MS122xx, MS124xx, MS21209, MA3279 and MA3329.
Key benefits
- • Repairs stripped or damaged threads in soft parent materials
- • Reinforces original-equipment production threads
- • Reduces weight versus a solid threaded bushing
- • Supports long service life in vibration-prone assemblies
Free-running inserts
The standard choice for general OEM and repair use. These tanged inserts install with a plain STI tap and mandrel and are commonly used for thread reinforcement in aircraft, avionics and industrial hardware.
Self-locking inserts
Designed for vibration and torsion resistance in dynamic assemblies such as engine accessories, rotating equipment and structural joints. These are specified where thread security is critical.
Core product range
High-demand sizes and part numbers
The sizes below reflect recurring aerospace and defence demand and are recommended as the core range for quick ordering and RFQ handling.
Inch series — free-running inserts
| Thread Size | Kit P/N | Bulk Insert P/N | MIL Spec | Helicoil Equivalent |
|---|---|---|---|---|
| 4-40 | 1208-014 | TNC-04C-0168 | MS122116 | — |
| 6-32 | 1208-016 | TNC-06C-0207 | MS122118 | — |
| 8-32 | 1208-018 | TNC-2C-0246 | MS122119 | 5521-2 |
| 10-24 | 1208-101 | TNC-3C-0285 | MS122120 | 5521-3 |
| 1/4-20 | 1208-104 | TNC-4C-0375 | MS122121 | 5521-4 |
| 5/16-18 | 1208-105 | TNC-5C-0469 | MS122122 | 5521-5 |
| 3/8-16 | 1208-106 | TNC-6C-0562 | MS122123 | 5521-6 |
| 7/16-14 | 1208-107 | TNC-7C-0656 | MS122124 | 5521-7 |
| 1/2-13 | 1208-108 | TNC-8C-0750 | MS122125 | 5521-8 |
| 10-32 | 1208-201 | TNF-3C-0285 | MS124695 | 5528-3 |
| 1/4-28 | 1208-204 | TNF-4C-0375 | MS124696 | 5528-4 |
Metric series — free-running inserts
| Thread Size | Kit P/N | Bulk Insert P/N | Spec No. | Helicoil Equivalent |
|---|---|---|---|---|
| M3 x 0.5 | 1221-303 | TNM-3X.5C-4.5 | MA3279-152 | 5546-3 |
| M4 x 0.7 | 1221-304 | TNM-4X.7C-6 | MA3279-154 | 5546-4 |
| M5 x 0.8 | 1221-305 | TNM-5X.8C-7.5 | MA3279-155 | 5546-5 |
| M6 x 1.0 | 1221-306 | TNM-6X1C-9 | MA3279-156 | 5546-6 |
| M8 x 1.25 | 1221-308 | TNM-8X1.25C-12 | MA3279-159 | 5546-8 |
| M10 x 1.5 | 1221-310 | TNM-10X1.5C-15 | MA3279-161 | 5546-10 |
| M12 x 1.75 | 3221-M12C | TNM-12X1.75C-18 | MA3279-164 | 5546-12 |
Self-locking inserts
| Thread Size | Bulk Insert P/N | Spec No. |
|---|---|---|
| 1/4-20 | TLC-4C-0375 | MS21209C4-15 |
| 5/16-18 | TLC-5C-0469 | MS21209C5-15 |
| 3/8-16 | TLC-6C-0562 | MS21209C6-15 |
| M5 x 0.8 | TLM-5X.8C-7.5 | MA3329-155 |
| M6 x 1.0 | TLM-6X1C-9 | MA3329-156 |
| M8 x 1.25 | TLM-8X1.25C-12 | MA3329-159 |
Certifications and standards
GLE supports customer and programme requirements with reference to ISO 9001:2015, AS9100 Rev D, NCAGE AS503 and military/aerospace specification cross-references.
Typical applications
Aircraft structure and engine repair, avionics housings, launch and test systems, GSE, spark plug thread repair and general MRO activities.
Installation tooling
STI taps, installation mandrels, tang break-off tools, insert-removal tools and repair kits are available as part of the complete thread repair solution.
Frequently asked questions
Common buyer questions
What is the difference between a Helicoil and a Perma-Coil insert?
They are the same family of helical wire thread inserts. 'Helicoil' is a widely used generic term, while Perma-Coil is KATO's aerospace-certified equivalent, cross-referenced size-for-size.
Which thread insert type should I choose?
Free-running inserts are used for general OEM and repair work, while self-locking inserts are preferred where vibration resistance and torsional stability are required.
Are these inserts aerospace-certified?
Yes. GLE supplies inserts and tooling that align with MS122xx, MS124xx, MS21209 and MA3279/MA3329 reference standards depending on the size and type.
Need a quick quote for Perma-Coil thread inserts?
Share your required thread size, insert type, quantity and application and our team will help you with the correct KATO part reference and lead-time guidance.
