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Caianwin Brass Threaded Inserts Review: Are Heat-Set M4 Inserts Right for Your 3D Prints?

Caianwin 50PCS Thread Insert M4 Brass Heat Set Insert for for Plastic and 3D Printing Components - Brass Metric Knurled Nuts
4.7
[3D Printing Compatibility]  Easily heat-embedable in blind or through holes for reliable fastening in 3D printed parts.
[Premium Brass Construction]  High-quality brass offers excellent heat conduction and corrosion resistance for durable inserts.
[Enhanced Grip Design]  45° knurling and precision threads maximize torque resistance and prevent thread slippage.
[Multiple Plastic Compatibility]  Works with PLA, PETG, ABS, PPS, PP and other thermoplastics for broad application.
[Bulk M4 Pack]  Contains 50 M4 x8.1 x6mm threaded inserts; verify size compatibility with your parts.
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Threaded inserts for plastic and 3D printing that create secure, durable metal threads for repeated use. Relief for makers who are tired of stripped or unreliable plastic fastening points. Are Caianwin Brass Threaded Inserts the right solution for your print and repair projects?

⚡ At a Glance
  • Holding Strength: 45-degree angled knurling and precision threading improve torque resistance and tensile strength
  • Best for: 3D printing hobbyists, repair technicians and small manufacturers working with thermoplastics
  • Not ideal for: Applications requiring metal-to-metal threads or non-thermoplastic materials

Brass M4 heat-set inserts sized 8.1 x 6 mm come in a pack of 50. Designed for embedding into thermoplastics using heat to form reliable threaded connections.


Secure, lasting threads – thanks to 45-degree angled knurling

Knurling cut at a 45-degree angle bites into softened plastic and increases surface area, while precise internal threading matches M4 fasteners. High-precision machining prevents thread misalignment and slippage during rotation.

Stronger fastenings resist loosening and stripping, making repeated assembly and disassembly practical without damaging the plastic part.

Quick, reliable installation – with heat-set design

Inserts are embedded using heat from a soldering iron or ultrasonic tool, allowing the plastic to melt slightly and flow into knurls and undercuts. Cooling locks the insert into place without the need for adhesives.

Fast installation speeds up assembly and repair work, and provides a consistent, repeatable method for adding metal threads to printed parts.

Broad compatibility with common 3D printing plastics – with brass construction

Brass offers excellent heat conduction for clean heat-set installation and inherent corrosion resistance. Inserts are specified for use with PLA, PETG, ABS, PPS, PP and other thermoplastics.

Works across most filament types used by makers and small manufacturers, reducing the need for different fastener solutions per material.

✨ The 4 Key Reasons for Caianwin Brass Threaded Inserts
  1. High-quality brass - Fast heat conduction for quick, consistent heat-set installation
  2. Precision M4 threading - Prevents thread slippage during repeated assembly and rotation
  3. Pack of 50 M4 inserts - Supplies enough inserts for several projects without interruptions
  4. Works with PLA, PETG, ABS and more - Compatible across common thermoplastics used in 3D printing
📋 Technical Details at a Glance
  • Material: Brass
  • Thread size: M4
  • Dimensions: 8.1 x 6 mm
  • Quantity: 50 pieces per pack
  • Installation method: Heat-set using soldering iron or ultrasonic insertion
❓ Frequently Asked Questions

Q: Can these inserts be used in 3D printed parts?

A: Yes, heat from a soldering iron or ultrasonic tool embeds the inserts into blind or through holes in 3D printed parts to create strong threaded connections.

Q: Which plastics are compatible with these inserts?

A: Compatible with all thermoplastics listed, including PLA, PETG, ABS, PPS and PP, plus other similar materials.

Q: What size and quantity are included?

A: Each pack contains 50 threaded inserts, size M4 with dimensions 8.1 x 6 mm.

🏆 Our Verdict

Ideal for makers, repair technicians and small-scale manufacturers who need reliable metal threads in plastic parts. High-quality brass construction, 45-degree knurling and heat-set installation deliver durable, corrosion-resistant threaded connections. Practical long-term value comes from repeatable performance and broad compatibility across common 3D printing materials.