Send a part number, a photo, or a whole BOM — we supply it and stand behind it. Worldwide shipping to 80+ countries.

HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-28 Thread Size - Screw-Locking Tangless Helical Inserts
HELI-COILScrew-Locking Tangless Helical Inserts

HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-28 Thread Size

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

Brand
HELI-COIL
Item
Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-28 Thread Size
Category
Screw-Locking Tangless Helical Inserts
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineer
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

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
View Full Spec Sheet

Technical Documents

No technical documents available for this product.
Request documentation
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

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 engine repair — HELI-COIL STI taps for M12x1.75 metric threads in aluminum alloy components
Automotive transmission rebuild — HELI-COIL STI taps for 7/16-14 UNC threads in cast iron housings
Industrial pump maintenance — HELI-COIL STI taps for #10-32 UNF threads in stainless steel pump bodies
Hydraulic cylinder repair — HELI-COIL STI taps for M6x1 metric threads in steel cylinder heads
General manufacturing — HELI-COIL STI taps for 9/16-18 UNF threads in machinery base plates

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.

You might also need

Burners & Combustion Pumps & Compressors Spare Parts All Products

More from HELI-COIL

View all HELI-COIL parts
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, 100 PK (MPN AT3585-4CW375). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-20; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, 100 PK (MPN AT3585-4CW375). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-20; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, Plain, 1,000 PK (MPN T3585-4C250S). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-28; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, Plain, 1,000 PK (MPN T3585-4C250S). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-28; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, Plain, 100 PK (MPN AT3585-4C500). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-20; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, 1/4"-20 Thread Size, Plain, 100 PK (MPN AT3585-4C500). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: 1/4"-20; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #4-40 Thread Size, Plain, 1,000 PK (MPN T3585-04C224S). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #4-40; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #4-40 Thread Size, Plain, 1,000 PK (MPN T3585-04C224S). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #4-40; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #6-32 Thread Size, Plain, 100 PK (MPN AT3585-06C207). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #6-32; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #6-32 Thread Size, Plain, 100 PK (MPN AT3585-06C207). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #6-32; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #2-56 Thread Size, Plain, 100 PK (MPN AT3585-02C129). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #2-56; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #2-56 Thread Size, Plain, 100 PK (MPN AT3585-02C129). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #2-56; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #4-40 Thread Size, Plain, 100 PK (MPN AT3585-04C168). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #4-40; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #4-40 Thread Size, Plain, 100 PK (MPN AT3585-04C168). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #4-40; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #10-24 Thread Size, Plain, 100 PK (MPN AT3585-3C190). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #10-24; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.
HELI-COIL
HELI-COIL Helical Insert: Tangless Tang Style, Screw-Locking, #10-24 Thread Size, Plain, 100 PK (MPN AT3585-3C190). Key specifications — Material Grade/Class: 18-8; Thread Direction: Right Hand; STI Tap Size: #10-24; Compatible Material: Metal; System of Measurement: Inch; Brand: HELI-COIL; Tensile Strength: 200,000 to 250,000 psi; Thread Type: Coarse.