10 Best M4 Inserts of 2025

Tested and Reviewed: Top 10 M4 Inserts deals with expert ratings from 8.1 to a perfect 10

March 2026 Edition

Editor's Choice

9.7

Yaocom

Yaocom 300 Pcs M4 Threaded Inserts M4 x D6 x L6 Heat Set Inserts Brass 3D Printing Knurled Metric Nuts for Plastic, 3D Printing Components

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Editor's bottom line:

“This m4 inserts is the best one we tested. In terms of quality, brand and price, we couldn't ask for more.”

Main Highlights

Bulk Package: you will get 300 pcs M4 threaded inserts that provides sufficient quantity to cater to your daily needs; Whether it's for 3D printing, computer products, electronic items, or circuit board fixing, our bulk package offers ample supply
Quality Brass Material: our M4 heat set inserts are made from quality brass; They exhibit robustness, a smooth surface, no burrs, and good mechanical properties which make them not easy to deform, ensuring a long lasting use
Easy Installation: experience ease and efficiency with our brass threaded inserts that are suitable for installation by ultrasonic or heat into the plastic matrix; No need for countersunk holes or countersunk holes, making the installation process easier
Precision Construction: our 3d printer brass inserts knurled feature precise construction; Each threaded insert comes with clear threads, uniform force and spacing, offering adequate torsion and tension for secure fixation
Securely Held: enjoy the stability offered by our threaded inserts for plastic; They feature an outer diameter that is embossed to form a certain friction and bite force; Once molded, they are not easy to slippage, ensuring they stay firmly in place

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Picked by 397 people today

9.5

ruthex

ruthex M4 Threaded Inserts - 50 Pieces RX-M4x8.1 Brass Heat Set Insert for Plastic Parts - Metric knurled Nuts - Insert by Heat into 3D Printing Components

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Main Highlights

M4 THREADED INSERTS FOR YOUR 3D PRINTED PARTS: The ruthex threaded nuts can be retrofitted by heat or ultrasound into parts of 3D printers from e.g. Anycubic or Prusa. With the help of heat from a soldering iron or ultrasonic, the insert nuts are simply embedded in a blind- or through hole
FIRM HOLDING WITH EASY APPLICATION: Thanks to the geometry of the threaded sleeve, it firmly holds in the pressure part. The opposing spiral-shaped knurled nuts ensure a high balanced tightening and loosening torque, as well as a high tightening force. Through the guide, insertion has been greatly simplified
STABLE & LONG-LASTING THREAD INSERTS: The inserts with internal thread lead free brass, which ensures optimum corrosion resistance and thermal conductivity. thermal conductivity. This means that each insert nut can be used for a long time and is easy to use. The reusability of the insert nut is also possible by carefully removing them from the pressure part when they are no longer needed
SUITABLE FOR A VARIETY OF PLASTICS: The inserts are designed for all thermoplastics. For example, the knurled nuts hold in PLA, PETG, ABS, PPS, PP and many more. As soon as the plastic of the part around the brass sleeve cools and hardens, the threaded sleeve is firmly anchored
PRACTICAL THREAD INSERT SET: The ruthex threaded inserts set are lead free and RX-M4x8,1 consists of 50 insert nuts with M4 internal thread and a length of 8.1 mm. The threaded sleeves can be inserted by ultrasonic and heat embedding

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9.5

Hanglife

HANGLIFE Heat-Set Threaded Inserts, M4 Heat Set Insert for 3D Printing Components and Plastic Parts - Brass Metric Knurled Nuts (100 Pieces)

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Main Highlights

Perfect Fit for Your 3D Printed Parts: Retrofit your 3D printed components seamlessly with our threaded inserts, effortlessly embedded using heat or ultrasound into blind- or through-holes. Providing a reliable and secure method for fastening components in 3D printing projects. Elevate the strength and functionality of your creations with ease.
Secure Hold with Simple Application: The opposite spiral-shaped knurled nuts provide a balanced high tightening torque, ensuring a stable connection. Our heat set inserts offer seamless installation onto plastic components, resisting torque and preventing pull-out.
Durable and Corrosion-Resistant: Crafted from high-quality brass, our threaded inserts provide optimal corrosion resistance and thermal conductivity. Exceptional durability and high resistance to breaking or deformation make them a reliable choice for various applications.
Versatile Compatibility with Plastics: Designed for all thermoplastics, including PLA, PETG, ABS, PPS, PP, and more, these inserts find applications in 3D printers, electrical molding machines, automotive plastic shells, and laptop molds. Their versatility ensures compatibility across a wide range of materials.
Practical Thread Insert Set: This M4x6x6 set includes 100 insert nuts with M4 internal thread, 6mm width, and 6.0mm length. Explore various dimensions of heat-set inserts at HANGLIFE to find the perfect fit for your specific needs. Drop down the variations to discover more choices.

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9.2

Ktehloy

Ktehloy 400Pcs Threaded Inserts, M2 M2.5 M3 M4 M5 M6 Female Thread Metric Knurled Nuts Assortment Kit, Brass Heat Set Insert for Plastic and 3D Printing Components (Threaded Inserts Ket)

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Main Highlights

Package Content- The package includes 400 high-quality metric threaded inserts for plastic heat-setting. With a large quantity available, it meets the needs for connecting numerous 3D printing accessories. The threaded brass inserts are approximately sized at M2 M2.5 M3 M4 M5 M6. Please ensure the nut's size matches your plastic parts effectively.
High-Quality Threaded Inserts- Crafted from top-tier brass materials, these threaded inserts boast outstanding thermal conductivity, corrosion resistance, and durability. They exhibit remarkable resistance against breakage and deformation. Withstanding temperatures exceeding 300°C / 572°F, they easily endure the harsh heat generated during plastic thermal shaping processes.
Precision Craftsmanship- High-precision and clear threading ensures stability and reliability, preventing thread slippage during rotation. The 45-degree angled knurling significantly enhances torque resistance and tensile strength, ensuring a stronger fastening. The embedded nuts feature guiding elements, eliminating the need for countersinking or recessing, making your work more convenient and efficient.
Easy to Use- Brass threaded inserts can be installed into components of a 3D printer through heating or ultrasonic methods, or molded during the injection process. They are also suitable for circuit board assembly and the electronics field. With a common soldering iron, you can easily place them into the holes of 3D prints.
Wide Application - These inserts are designed for use with all thermoplastics, including materials like PLA, PETG, ABS, PPS, PP, and others. Whether installing them in 3D printed objects, injection-molded plastic parts, automotive plastic casings, or laptop shells, these inserts offer reliable and durable solutions.

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9.0

Kadrick

150 Pcs M4 Threaded Inserts for Plastic with Heat Set Tip,M4(6mm-10mm Hight)5.5mm Heat Set Inserts Kit,Brass Inserts for 3D Pringting

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Main Highlights

Standard M4 Size & Included Tip: M4 size (5.5mm OD, 6mm-10mm Height, 0.7mm Pitch) threaded inserts, compatible with M4 screws. Includes a matching soldering iron tip for installation.
Ideal Heat-Set Inserts for 3D Printing: Perfect brass threaded inserts for plastics. Easily embed into 3D printed parts or thermoplastics (PLA, ABS, PETG) using a soldering iron with the included Heat Set Insert Tips.
Premium Lead-Free Brass & Durability: Made from high-quality, lead-free brass for excellent heat conduction, corrosion resistance, and strength. Withstands over 300°C / 572°F (ideal for heat setting), resisting breakage and deformation.
Knurled Grip & Easy Installation: Knurled surface (45° design) provides superior pull-out resistance and torque holding vs. smooth inserts. Built-in lead-in allows easy installation into plastic without countersinking.
Organized Kit & Warranty: Supplied in a reinforced, compartmentalized box (kit style) with clear labeling for easy use. Backed by Kadrick's testing and a 24-month warranty.

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8.8

FFVRVSS

FFVRVSS 320+6Pcs M2 M2.5 M3 M4 M5 Premium Brass Threaded Inserts, Metric Brass Knurled Nuts Assortment Kit, with Heat Set Insert Tool, for Plastic and 3D Printing Components, All-in-one

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Main Highlights

Ultra AffordableBased on real user data, weve included the 5 most commonly used metric knurled nut sizes for 3D printers: M2, M2.5, M3, M4, and M5. This kit also comes with an upgraded extended-tip heat set toolperfectly compatible, Skip the hassle of buying tools separately; this one-stop solution checks all your boxes with just one purchase.
Top-Tier Brass QualityMade from premium brass, our heat set inserts and heat set tool offer exceptional thermal conductivity. The heavy-duty brass resists oxidation, corrosion, breakage, and deformation, outperforming flimsy alternatives that fail quickly. These inserts stay strong and reliable for years, ensuring rock-solid fastenings even in harsh conditions.
Precision Design for Secure GripHigh-precision threading prevents slippage during installation, while 45-degree spiral knurling boosts torque resistance and tensile strength. The knurled exterior creates tight friction with plastic, delivering stronger holding power than straight-threaded inserts. Built-in guides eliminate the need for countersinkingjust insert and secure for a firm fit.
Clear Identification & CategorizationEach threaded insert size is stored in its own sealed compartment, so no more tangled messes. Paired with clear, easy-to-read size labels, you can grab the right one in seconds and store them neatly afterward. Keep your workspace organized, even with long-term, Even non-professionals can handle it with total ease.
Universal Compatibility & Quality AssuranceWorks seamlessly with all thermoplastics (PLA, PETG, ABS, PPS, PP) and diverse projectsfrom 3D-printed parts to automotive shells and laptop casings. Every piece undergoes strict quality inspections. Whether for electronics, toys, or furniture, these inserts deliver long-lasting, reliable retention. Buy with confidence!

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8.6

PEUTIER

120pcs 3D Printing Brass Nuts, M4x6x6mm Threaded Heat Set Inserts M4 Knurled Brass Nuts Heat Embedment Nut for 3D Printing Parts Loptop Automotive Plastic Shell

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Main Highlights

Package Content: You will get 120 pieces of threaded heat set inserts, sufficient quantity can meet your needs of connecting numerous 3D printing accessories. Each knurled brass nut measures about M4x6x6mm / M4x0.24x0.24inch, please ensure that the size of the nuts can well match your 3D printer.
Premium Material: The threaded inserts for 3D printing are made of premium brass, extremely sturdy, not easy to break or deform, also can withstand high temperature above 300°C / 572°F. Excellent thermal conductivity also makes your 3D printer to work more effectively.
Easy to Install: The knurled brass nuts can be easily installed into the the tapered holes of 3D printers by heating, also can be molded by injection molding. The 3D printing brass nuts with full knurled patterns can perfectly match with your 3D printers. Practical nuts make your 3D printer work well.
Good Workmanship: With clean surface and twill thread knurled patterns, the nuts can be installed onto 3D printers and fit perfectly and wont scratch your precious 3D printing parts. The smaller diameter of the front end of the nut allows you insert them into 3D printing hole precisely. Inclined thread knurls increase the torque resistance, so they can be fixed on the 3D printers tightly.
Wide Application: These m4 threaded insert nuts can be inserted into various plastics, such as PC, PA, PLA, ABS, PETG, etc. Suitable for installing on 3D printers, electrical molding machines, electrical injection molding, automotive or laptop molding plastic shells, etc.

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8.3

Likitcok

M4 Threaded Inserts – Heat Set Inserts for 3D Printing and Plastic Parts, Metric Knurled Design for Secure Installation 100 Pcs

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Main Highlights

Designed for 3D Printing and Plastic Parts These M3 brass heat-set inserts are specifically designed for 3D printers and plastic components, providing strong, secure connections for various printing and assembly projects
Precision Metric Threads and Knurled Design Each insert features precision metric threads and a unique knurled design, ensuring a tight, secure fit in plastic materials, preventing slipping or loosening
Easy Heat Set Installation These inserts are fully compatible with heat-set tools, making installation fast and easy. They improve efficiency, especially for applications that require high precision and stability
Durable Brass Material Made from high-quality brass, these inserts offer excellent corrosion resistance and anti-oxidation properties, ensuring long-term reliability and durability
Versatile, Wide Range of Uses In addition to 3D printing projects, these inserts are ideal for DIY projects, electronics, home repairs, and plastic part installations, making them highly versatile

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8.1

Pofsnnx

100Pcs Pofsnnx M4 Threaded Inserts, Brass Heat Set Insert for Plastic and 3D Printing Components, Metric Knurled Nut Classification Combination Kit(M4xL4xD6, M4xL8xD6)

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Main Highlights

Premium Brass Material: Made from high-quality brass for excellent heat conduction and corrosion resistance, ensuring durable, long-lasting threaded connections in plastic and 3D-printed parts
Strong & Reliable Hold: Knurled outer design grips tightly into plastic, preventing rotation or loosening, while high pull-out resistance ensures secure fastening even under stress
Easy Heat-Set Installation: Quickly melts into place using a soldering iron or heat-set tool (not included)no glue or extra hardware needed for a clean, professional finish
Perfect for 3D Printing & Plastic Assembly: Ideal for PLA, ABS, PETG, Nylon, and other thermoplastics, widely used in 3D printing, robotics, RC models, electronics enclosures, and DIY repairs
100PCS Value Pack: Cost-effective bundle for frequent usersenough for multiple projects . Includes M4*4*6mm and M4*8*6mm variants for versatility

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8.1

Ktehloy

Ktehloy 120Pcs M4 Threaded Inserts, M4 Female Thread Metric Knurled Nuts Assortment Kit, Brass Heat Set Insert for Plastic and 3D Printing Components (M4x4x6, M4x6x6)

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Main Highlights

Package Content- The package includes 120 high-quality metric threaded inserts for plastic heat-setting. With a large quantity available, it meets the needs for connecting numerous 3D printing accessories. The threaded brass inserts are approximately sized at M4x4x6, M4x6x6(mm). Please ensure the nut's size matches your plastic parts effectively.
High-Quality Threaded Inserts- Crafted from top-tier brass materials, these threaded inserts boast outstanding thermal conductivity, corrosion resistance, and durability. They exhibit remarkable resistance against breakage and deformation. Withstanding temperatures exceeding 300°C / 572°F, they easily endure the harsh heat generated during plastic thermal shaping processes.
Precision Craftsmanship- High-precision and clear threading ensures stability and reliability, preventing thread slippage during rotation. The 45-degree angled knurling significantly enhances torque resistance and tensile strength, ensuring a stronger fastening. The embedded nuts feature guiding elements, eliminating the need for countersinking or recessing, making your work more convenient and efficient.
Easy to Use- Brass threaded inserts can be installed into components of a 3D printer through heating or ultrasonic methods, or molded during the injection process. They are also suitable for circuit board assembly and the electronics field. With a common soldering iron, you can easily place them into the holes of 3D prints.
Wide Application - These inserts are designed for use with all thermoplastics, including materials like PLA, PETG, ABS, PPS, PP, and others. Whether installing them in 3D printed objects, injection-molded plastic parts, automotive plastic casings, or laptop shells, these inserts offer reliable and durable solutions.

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Our Best Overall Choice

Best Choice

9.7

Yaocom

Yaocom 300 Pcs M4 Threaded Inserts M4 x D6 x L6 Heat Set Inserts Brass 3D Printing Knurled Metric Nuts for Plastic, 3D Printing Components

Free Shipping

Editor's bottom line:

“This is the best one we tested. In terms of quality, brand and price, we couldn't ask for more.”

Main Highlights

Bulk Package: you will get 300 pcs M4 threaded inserts that provides sufficient quantity to cater to your daily needs; Whether it's for 3D printing, computer products, electronic items, or circuit board fixing, our bulk package offers ample supply
Quality Brass Material: our M4 heat set inserts are made from quality brass; They exhibit robustness, a smooth surface, no burrs, and good mechanical properties which make them not easy to deform, ensuring a long lasting use
Easy Installation: experience ease and efficiency with our brass threaded inserts that are suitable for installation by ultrasonic or heat into the plastic matrix; No need for countersunk holes or countersunk holes, making the installation process easier
Precision Construction: our 3d printer brass inserts knurled feature precise construction; Each threaded insert comes with clear threads, uniform force and spacing, offering adequate torsion and tension for secure fixation
Securely Held: enjoy the stability offered by our threaded inserts for plastic; They feature an outer diameter that is embossed to form a certain friction and bite force; Once molded, they are not easy to slippage, ensuring they stay firmly in place

Show Price

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10 Best M4 Inserts of 2025

Tested and Reviewed: Top 10 M4 Inserts deals with expert ratings from 8.1 to a perfect 10

Yaocom

Yaocom 300 Pcs M4 Threaded Inserts M4 x D6 x L6 Heat Set Inserts Brass 3D Printing Knurled Metric Nuts for Plastic, 3D Printing Components

Editor's bottom line:

Main Highlights

ruthex

ruthex M4 Threaded Inserts - 50 Pieces RX-M4x8.1 Brass Heat Set Insert for Plastic Parts - Metric knurled Nuts - Insert by Heat into 3D Printing Components

Main Highlights

Hanglife

HANGLIFE Heat-Set Threaded Inserts, M4 Heat Set Insert for 3D Printing Components and Plastic Parts - Brass Metric Knurled Nuts (100 Pieces)

Main Highlights

Ktehloy

Ktehloy 400Pcs Threaded Inserts, M2 M2.5 M3 M4 M5 M6 Female Thread Metric Knurled Nuts Assortment Kit, Brass Heat Set Insert for Plastic and 3D Printing Components (Threaded Inserts Ket)

Main Highlights

Kadrick

150 Pcs M4 Threaded Inserts for Plastic with Heat Set Tip,M4*(6mm-10mm Hight)*5.5mm Heat Set Inserts Kit,Brass Inserts for 3D Pringting

Main Highlights

FFVRVSS

FFVRVSS 320+6Pcs M2 M2.5 M3 M4 M5 Premium Brass Threaded Inserts, Metric Brass Knurled Nuts Assortment Kit, with Heat Set Insert Tool, for Plastic and 3D Printing Components, All-in-one

Main Highlights

PEUTIER

120pcs 3D Printing Brass Nuts, M4x6x6mm Threaded Heat Set Inserts M4 Knurled Brass Nuts Heat Embedment Nut for 3D Printing Parts Loptop Automotive Plastic Shell

Main Highlights

Likitcok

M4 Threaded Inserts – Heat Set Inserts for 3D Printing and Plastic Parts, Metric Knurled Design for Secure Installation 100 Pcs

Main Highlights

Pofsnnx

100Pcs Pofsnnx M4 Threaded Inserts, Brass Heat Set Insert for Plastic and 3D Printing Components, Metric Knurled Nut Classification Combination Kit(M4xL4xD6, M4xL8xD6)

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Ktehloy

Ktehloy 120Pcs M4 Threaded Inserts, M4 Female Thread Metric Knurled Nuts Assortment Kit, Brass Heat Set Insert for Plastic and 3D Printing Components (M4x4x6, M4x6x6)

Main Highlights

Our Best Overall Choice

Yaocom

Yaocom 300 Pcs M4 Threaded Inserts M4 x D6 x L6 Heat Set Inserts Brass 3D Printing Knurled Metric Nuts for Plastic, 3D Printing Components

Editor's bottom line:

Main Highlights

Deals are Live

150 Pcs M4 Threaded Inserts for Plastic with Heat Set Tip,M4(6mm-10mm Hight)5.5mm Heat Set Inserts Kit,Brass Inserts for 3D Pringting