M3 Brass Heat-Set Threaded Insert – Ø4.5 × 4mm

M3 Brass threaded insert for creating a reusable metal thread in thermoplastic parts. It is installed using controlled heat, allowing the surrounding plastic to soften around the external knurling and retain the insert as it cools.

Its opposing diagonal knurls increase contact with the plastic and help resist both rotation and pull-out. It is particularly useful for 3D-printed parts that must be disassembled repeatedly or withstand more tightening than a thread formed directly in plastic.

Features and dimensions

• Internal thread: M3.
• Nominal outside diameter: 4.5mm.
• Nominal length: 4mm.
• Material: Brass, a copper alloy.
• Thread: through-threaded.
• External surface: bidirectional knurling.
• Recommended installation: thermal insertion into thermoplastics.

Sales unit

The price is for one insert. The screw and installation tools are sold separately.

Typical applications

• 3D-printed electronic enclosures.
• 3D-printer extruders, toolheads and brackets.
• Mounting controller boards, sensors and fans.
• Parts requiring periodic disassembly.
• Thermoplastic prototypes and mechanisms.

Designing the receiving hole

The M3 thread identifies the compatible screw but does not determine the receiving-hole diameter. This insert has a nominal outside diameter of 4.5mm and a length of 4mm.

Hole design must account for:

• The insert’s actual outside diameter.
• Printed material and shrinkage.
• Part orientation and extrusion width.
• The amount of material surrounding the hole.
• Required depth for both insert and screw.

There is no universal hole diameter that behaves identically with every printer and material. Print a small test piece containing several hole sizes before manufacturing the final component.

Voron printer compatibility

M3 inserts are widely used in Voron printers and modifications, but the relevant bill of materials and printed-part design must be checked.

This product measures M3 × Ø4.5 × 4mm, while many current Voron designs specify inserts measuring approximately M3 × Ø5 × 4mm. It may be used when the receiving hole is designed or adjusted for a 4.5mm outside diameter, but it is not a universal substitute for every Voron insert.

Recommended installation

1. Prepare a straight hole with sufficient surrounding material.
2. Heat the insert using a temperature-controlled soldering iron, preferably with a dedicated heat-set-insert tip.
3. Press it in perpendicularly using gentle, steady pressure.
4. Stop when it is flush without sinking it excessively.
5. Hold it still and allow the plastic to cool completely.
6. Check alignment and clean the thread entrance before inserting the screw.

The appropriate temperature depends on the thermoplastic. Apply only enough heat to soften it: excessive temperature may degrade the material, distort the hole or weaken the joint.

Precautions

• Do not install too close to thin walls or edges.
• Do not press the insert in cold, as this may crack the part or separate printed layers.
• Do not use the screw to pull the insert into place during thermal installation.
• Make sure the screw cannot bottom out or push the insert from the part.
• Resin, thermoset, wood and non-melting materials require a different installation method.

Other thread sizes

• M4 Brass threaded insert, Ø6 × 8mm.
• M5 Brass threaded insert, Ø7 × 10mm.