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

HELI-COIL Screw-Locking Tanged Helical Insert, 1/4"-28, 100 PK - Screw-Locking Tanged Helical Inserts
HELI-COILScrew-Locking Tanged Helical Inserts

HELI-COIL Screw-Locking Tanged Helical Insert, 1/4"-28, 100 PK

HELI-COIL Helical Insert: Tanged Tang Style, Screw-Locking, 100 PK (MPN A3591-4CNW250). These 18-8 stainless steel inserts feature a 1/4"-28 fine thread, right-hand direction, and a tensile strength of 200,000 to…

SKU 3G-OTH-528871

Also listed as: A35914CNW250 · A3591 4CNW250

Brand
HELI-COIL
Item
Screw-Locking Tanged Helical Insert, 1/4"-28, 100 PK
Category
Screw-Locking Tanged Helical Inserts
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineerMessage via Telegram
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

Local availability & support — Singapore

Local office
20 Woodlands Link #09-05, Singapore 738733
Phone
+65 8878 8355
Delivery
Same-day or next-business-day delivery within Singapore for in-stock items; 7–14 days for factory-order parts from Europe.
Payment
Invoicing in SGD. PayNow, bank transfer, and corporate PO accepted.
Ships to
Singapore

Technical Specifications

HELI-COIL
Manufacturer Part Number
A3591-4CNW250
Type
Screw-Locking, 100 PK
Tensile Strength
200,000 to 250,000 psi
Finish Type
Dry Film Lubricant
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

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

HELI-COIL Helical Insert: Tanged Tang Style, Screw-Locking, 100 PK (MPN A3591-4CNW250). These 18-8 stainless steel inserts feature a 1/4"-28 fine thread, right-hand direction, and a tensile strength of 200,000 to 250,000 psi. Designed for metal substrates, they include a dry film lubricant finish and require an STI tap size of 1/4"-28.

Frequently Asked Questions

What is a HELI-COIL screw-locking helical insert used for?

A HELI-COIL screw-locking helical insert repairs or reinforces threads in metal substrates. The 18-8 stainless steel insert with a dry film lubricant provides a locking action that resists vibration loosening, making it ideal for automotive, aerospace, and industrial applications requiring reliable thread strength.

What are the specifications of the HELI-COIL A3591-4CNW250 insert?

This HELI-COIL insert has a 1/4"-28 fine thread, right-hand direction, and a tensile strength of 200,000 to 250,000 psi. It is made of 18-8 stainless steel, requires an STI tap size of 1/4"-28, and comes in a 100-pack with a dry film lubricant finish for metal substrates.

Where to buy HELI-COIL helical inserts worldwide?

3G Electric supplies HELI-COIL helical inserts worldwide. As a global industrial solutions provider, we handle full logistics and customs clearance to deliver the A3591-4CNW250 screw-locking inserts to your facility. Contact us for availability and lead time on your order.

How to install a HELI-COIL tanged tang insert?

To install a HELI-COIL tanged tang insert, drill the hole to the specified size, tap it using the correct STI tap (1/4"-28 for this insert), then use a tang-style installation tool to wind the insert into the tapped hole. After installation, break off the tang with a punch for a flush finish.

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 tanged 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
This HELI-COIL tanged helical insert is designed for screw-locking applications in metal substrates. It features a 1"-12 fine thread, right-hand direction, and an overall length of 1 1/2 in. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi, it requires an STI tap size of 1"-12. Commonly used to repair or reinforce threads in metal components
HELI-COIL
This HELI-COIL tanged helical insert is designed for screw-locking applications in metal substrates. It features a 1"-12 fine thread, right-hand direction, and an overall length of 1 1/2 in. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi, it requires an STI tap size of 1"-12. Commonly used to repair or reinforce threads in metal components
Screw-locking tanged helical insert for repairing or reinforcing threads in metal. #6-32 coarse thread, right-hand direction, 200,000 psi tensile strength, Nitronic 60 material, plain finish. Supplied in a 100-piece pack
HELI-COIL
Screw-locking tanged helical insert for repairing or reinforcing threads in metal. #6-32 coarse thread, right-hand direction, 200,000 psi tensile strength, Nitronic 60 material, plain finish. Supplied in a 100-piece pack
This HELI-COIL screw-locking tanged helical insert is made from 18-8 stainless steel with a dry film lubricant finish. It has a right-hand M6-1.00 coarse thread and a tensile strength of 200,000 to 250,000 psi. The insert requires a 6.25 mm drill bit and an M6-1.00 STI tap. It is used to repair or reinforce threads in metal components, providing wear-resistant threads in applications such as automotive, aerospace, and industrial machinery
HELI-COIL
This HELI-COIL screw-locking tanged helical insert is made from 18-8 stainless steel with a dry film lubricant finish. It has a right-hand M6-1.00 coarse thread and a tensile strength of 200,000 to 250,000 psi. The insert requires a 6.25 mm drill bit and an M6-1.00 STI tap. It is used to repair or reinforce threads in metal components, providing wear-resistant threads in applications such as automotive, aerospace, and industrial machinery
Screw-locking tanged helical insert for repairing or reinforcing threads in metal. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi. Features #10-32 fine right-hand threads and a plain finish. Supplied in a 1,000-piece pack
HELI-COIL
Screw-locking tanged helical insert for repairing or reinforcing threads in metal. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi. Features #10-32 fine right-hand threads and a plain finish. Supplied in a 1,000-piece pack
Screw-locking helical insert for repairing or reinforcing tapped threads in metal. Features a tanged tang style for installation, with a 1"-8 coarse thread and 1 1/2 in overall length. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi. Requires a 1"-8 STI tap for installation
HELI-COIL
Screw-locking helical insert for repairing or reinforcing tapped threads in metal. Features a tanged tang style for installation, with a 1"-8 coarse thread and 1 1/2 in overall length. Made from 18-8 stainless steel with a tensile strength of 200,000 to 250,000 psi. Requires a 1"-8 STI tap for installation
Screw-locking tanged helical insert for repairing or reinforcing threads in metal substrates. Features 18-8 stainless steel construction, plain finish, and 5/16"-24 fine thread. Requires STI tap size 5/16"-24. Supplied in a 100-piece pack
HELI-COIL
Screw-locking tanged helical insert for repairing or reinforcing threads in metal substrates. Features 18-8 stainless steel construction, plain finish, and 5/16"-24 fine thread. Requires STI tap size 5/16"-24. Supplied in a 100-piece pack
Screw-locking tanged helical insert for repairing or strengthening threads in metal. #4-40 thread size, coarse thread, right-hand direction. Made of 18-8 stainless steel with plain finish, tensile strength 200,000 to 250,000 psi. Requires #4-40 STI tap. Supplied in pack of 1,000
HELI-COIL
Screw-locking tanged helical insert for repairing or strengthening threads in metal. #4-40 thread size, coarse thread, right-hand direction. Made of 18-8 stainless steel with plain finish, tensile strength 200,000 to 250,000 psi. Requires #4-40 STI tap. Supplied in pack of 1,000
Screw-locking tanged helical insert for #6-32 coarse threads, made from Nitronic 60 with a tensile strength of 200,000 psi. Right-hand thread direction, plain finish. Supplied in a 100-piece pack. Used to repair or reinforce internal threads in metal substrates
HELI-COIL
Screw-locking tanged helical insert for #6-32 coarse threads, made from Nitronic 60 with a tensile strength of 200,000 psi. Right-hand thread direction, plain finish. Supplied in a 100-piece pack. Used to repair or reinforce internal threads in metal substrates