Description

Knurled Brass Threaded Inserts for 3D Printed Parts

Add strong, reusable metal threads to any 3D printed part with knurled brass heat-set inserts. Press them into a printed hole using a soldering iron and they melt into the surrounding plastic, locking in place with deep knurling that grips from all directions. The result is a durable, wear-resistant threaded connection that can be assembled and disassembled repeatedly without stripping — something printed threads can’t do.

Sold individually so you buy exactly what you need. Available in M2.5 through M6 with short, standard, and long length options.

Available Sizes

M2.5

M2.5 Short — 5mm OD × 6mm length

M3

M3 Short — 5mm OD × 6mm length
M3 Standard — 5mm OD × 8mm length
M3 Long — 5mm OD × 10mm length

M4

M4 Short — 6mm OD × 6mm length
M4 Standard — 6mm OD × 8mm length
M4 Long — 6mm OD × 10mm length

M5

M5 Short — 7mm OD × 6mm length
M5 Standard — 7mm OD × 8mm length
M5 Long — 7mm OD × 10mm length

M6

M6 Standard — 8mm OD × 10mm length
M6 Long — 8mm OD × 12mm length

How to Install

Design a hole in your 3D model slightly smaller than the insert’s outer diameter (typically 0.1–0.2 mm smaller). Print the part, place the insert on the hole, and press it in using a soldering iron set to 200–230°C for PLA or 250–270°C for PETG and ABS. Let the heat melt the plastic — gentle pressure is all that’s needed. The insert sinks into position and the knurling locks into the surrounding material as it cools.

For best results, use a heat insert adapter tip on your soldering iron — it centres the insert and drives it in straight. See our Soldering Iron Adapter Kit for Heat Inserts.

Why Heat-Set Inserts Over Printed Threads?

Printed threads strip easily, especially in PLA. Heat-set brass inserts provide metal threads that handle repeated assembly cycles without wear, accept standard metric bolts and machine screws, and distribute clamping force evenly into the surrounding plastic. They’re the standard approach for any functional 3D printed part that needs bolted connections.

Materials

Made from corrosion-resistant brass with deep knurling for maximum mechanical grip. Compatible with PLA, PLA+, PETG, ABS, ASA, nylon, and PC printed parts.

Brass inserts are sold individually