Threaded Knurled Insert Nuts Assortment Kit of M5 M6 90PCS for 3D Printing

Specifications

• Material: High-strength Brass
• Thread Standard: Metric M5 and M6
• Total Quantity: 90 Pieces (Assorted lengths)
• Insertion Method: Thermal (Hot Melt / Soldering Iron) or Ultrasonic
• Knurling Profile: Opposing Diagonal / Spiral
• Compatible Materials: PLA, PETG, ABS, ASA, TPU, Polycarbonate
• Application: 3D Printing, Injection Molding, DIY Enclosures
• Kit Packaging: Compartmentalized Plastic Storage Box

Minimum hardware to get started:

• Soldering Iron : to precisely heat the brass insert so it melts the surrounding thermoplastic and sinks into the pilot hole.
• 3D Printed Part with Pilot Holes : to receive the insert (the hole must be slightly smaller than the outer knurled diameter of the insert to allow the melted plastic to flow into the knurls).
• M5 or M6 Machine Screws : to fasten your components together once the plastic has cooled and locked the insert in place.

Safety Warnings:

• Burn Hazard: The brass inserts conduct heat extremely well and will remain dangerously hot for several minutes after insertion. Never touch them bare-handed until fully cooled.
• Fumes & Ventilation: Melting thermoplastics like ABS and ASA releases toxic fumes. Ensure your workspace is well-ventilated during the insertion process.
• Push-Through Risk: Applying too much downward pressure with the soldering iron can cause the insert to push entirely through thin-walled 3D printed parts. Let the heat do the work, not physical force.

Accessories
Included in the Box:

• 90× Assorted M5 and M6 Brass Heat Set Insert Nuts (Various Lengths)
• 1× Compartmented Plastic Storage Box

Frequently Asked Questions

• Which 3D printing filaments are compatible with these brass inserts?
  These inserts work perfectly with any thermoplastic, including PLA, PETG, ABS, ASA, PC, and TPU.
• Can I use these inserts with resin (SLA/DLP) 3D prints?
  No, standard 3D printing resins are thermosets, not thermoplastics, so they will burn or crack rather than melt around the insert.
• Are these inserts suitable for injection-molded parts?
  Yes, they can be thermally pressed into pre-molded holes in thermoplastic injection-molded enclosures.
• What size should I make the hole in my 3D design for an M5 insert?
  The pilot hole diameter should be slightly smaller than the outer diameter of the insert's knurling; typically around 6.8mm to 7.2mm for standard M5 inserts, but always test print a small block first.
• What temperature should I set my soldering iron to for PLA?
  Set your iron between 190°C and 210°C; you want it just hot enough to melt the plastic locally without burning it.
• Do I need a higher temperature for ABS or ASA?
  Yes, ABS and ASA require higher melting temperatures, so adjust your soldering station to 250°C – 270°C for a smooth insertion.
• Can I use a lighter or a blowtorch to heat the insert instead of a soldering iron?
  No, open flames offer zero temperature control and will likely oxidize the brass, warp your part, and severely burn the surrounding plastic.
• Do I absolutely need special soldering iron tips to install these?
  While not strictly required, specific heat-set insert tips are highly recommended as they prevent the insert from sticking to the iron and being pulled back out.
• Should I insert the nut from the front or the back of the part?
  Whenever possible, insert from the side opposite to where the pulling force will be applied; this maximizes pull-out resistance as the screw pulls the insert against the plastic shoulder.
• Do I need to add superglue or epoxy along with the insert?
  No, the melted thermoplastic flowing into the opposing spiral knurls provides a mechanical lock that is far stronger than glue.
• How thick should the plastic walls be around the insert?
  Maintain at least 2mm to 3mm of solid wall thickness (using high infill or extra perimeters) around the pilot hole to prevent the plastic from bulging or splitting during insertion.
• Do I need to tap the plastic hole with a thread tap before inserting?
  No, the hole should be completely smooth; the brass insert itself provides the threads once melted into place.
• Can I remove an insert once it has been installed?
  You can heat it up again with a soldering iron and pull it out, but this usually destroys the surrounding plastic hole, making it difficult to reinstall securely.