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HELI-COIL Screw-Locking Tangless Helical Insert - Screw-Locking Tangless Helical Inserts
HELI-COILScrew-Locking Tangless Helical Inserts

HELI-COIL Screw-Locking Tangless Helical Insert

The HELI-COIL Helical Insert (Tangless Tang Style) is a screw-locking, plain finish insert in a 100-piece pack, with a 1/4"-28 fine thread, right-hand direction, and 18-8 material grade. It offers a tensile strength…

SKU 3G-OTH-532469

Also listed as: AT35914C375 · AT3591 4C375

Brand
HELI-COIL
Item
Screw-Locking Tangless Helical Insert
Part Number
AT3591-4C375
Category
Screw-Locking Tangless Helical Inserts
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Local availability & support — Singapore

Local office
20 Woodlands Link #09-05, Singapore 738733
Phone
+65 8878 8355
Payment
Invoicing in SGD. PayNow, bank transfer, and corporate PO accepted.

Technical Specifications

HELI-COIL
Manufacturer Part Number
AT3591-4C375
Type
Screw-Locking, Plain, 100 PK
Tensile Strength
200,000 to 250,000 psi
Finish Type
Plain
Thread Size
1/4"-28
Thread Type
Fine
STI Tap Size
1/4"-28
Thread Direction
Right Hand
Compatible Material
Metal
Material Grade/Class
18-8
System of Measurement
Inch

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HELI-COIL Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The HELI-COIL Helical Insert (Tangless Tang Style) is a screw-locking, plain finish insert in a 100-piece pack, with a 1/4"-28 fine thread, right-hand direction, and 18-8 material grade. It offers a tensile strength of 200,000 to 250,000 psi, is compatible with metal, and uses an STI tap size of 1/4"-28. 3G Electric interprets demand and delivers this genuine industrial insert across 14 departments—with specialist depth in combustion, pumps, and controls—ensuring you get the right answer, not just a catalog.

Frequently Asked Questions

What is a HELI-COIL Tangless helical insert used for?

A HELI-COIL Tangless helical insert repairs or reinforces threads in metal components, providing a strong, wear-resistant internal thread. It is commonly used in automotive, aerospace, and industrial maintenance to restore stripped threads without replacing the entire part.

What are the specifications of the HELI-COIL AT3591-4C375 insert?

The HELI-COIL AT3591-4C375 is a screw-locking, tangless helical insert with a 1/4\"-28 fine thread, right-hand direction, and 18-8 material grade. It offers a tensile strength of 200,000 to 250,000 psi, is compatible with metal, and comes in a 100-piece pack with plain finish.

Where to buy HELI-COIL helical inserts in worldwide?

3G Electric supplies and delivers genuine HELI-COIL helical inserts worldwide. As a global industrial solutions provider, we handle full logistics and customs clearance to ensure your order arrives at your facility, no matter the location.

How to install a tangless helical insert?

To install a tangless helical insert, drill the hole to the specified STI tap size (1/4\"-28 for this insert), tap the hole with the corresponding STI tap, then use a tangless installation tool to wind the insert into the threaded hole. No tang removal step is needed.

Used in

Common applications for HELI-COIL
Aerospace — Tangless screw-locking HELI-COIL inserts in 18-8 stainless steel for vibration-resistant threaded joints in airframe and engine components.
Automotive — Free-running tanged HELI-COIL inserts in metric sizes for repairing stripped threads in aluminum engine blocks and transmission housings.
Industrial machinery — STI taps and prewinder installation tools for on-site repair of threaded holes in cast iron and steel machine frames.
Oil and gas — Nitronic 60 HELI-COIL inserts for galling resistance in stainless steel valve bodies and pump housings exposed to corrosive media.
MRO and maintenance — HELI-COIL thread repair kits containing inserts, drill, tap, and installation tool for restoring damaged threads without replacing the parent component.
Electrical equipment — Screw-locking tangless HELI-COIL inserts for securing fasteners in metal enclosures and control panels subject to vibration.
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HELI-COIL Products

3G Electric supplies HELI-COIL screw-locking tangless helical inserts. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

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Screw-locking tangless helical insert for repairing or reinforcing threads in metal. Made from 18-8 stainless steel with tensile strength 200,000 to 250,000 psi. Features #4-40 coarse right-hand thread and plain finish. Tangless design eliminates need to break off tang after installation. Pack of 100
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HELI-COIL
Screw-locking tangless helical insert for repairing or reinforcing threads in metal. Made from 18-8 stainless steel with dry film lubricant finish, fine right-hand thread, and tensile strength of 200,000 to 250,000 psi. Requires STI tap size #10-32. Pack of 100

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