Two Approaches: Printed Threads vs Inserts
By Inno Uncle
You can either print the thread directly into the part or install a metal insert afterward. Printed threads work for low-load, hand-tightened applications. For anything that will be tightened repeatedly or carry load, metal inserts are the safer choice. The decision usually comes down to how much torque the joint needs and how often it will be assembled.
Designing Printed Threads
- Use metric threads when possible: M3, M4, and M6 threads are easier to print reliably than fine-pitch options.
- Keep walls thick: Leave at least three perimeters around the thread root to prevent cracks.
- Print in the correct orientation: Align the thread axis vertically so each layer forms a clean ring instead of a staircase.
- Increase resolution: A 0.12 mm layer height produces much cleaner threads than 0.28 mm.
Installing Threaded Inserts
For thermoplastics, heat-set inserts are the most reliable. Press them in with a soldering iron set to around 200°C, letting the plastic flow around the knurls. Do not force the insert all the way in one push. Let it sink gradually so the surrounding plastic does not bulge or crack. If your part is thin, choose a shorter insert or add a washer flange to spread the load.
Material Selection
PLA threads hold up for light-duty projects but strip easily under torque. PETG is more forgiving, while ABS and ASA handle heat and vibration better. For high-load assemblies, print the housing in nylon or PETG and pair it with quality brass inserts. Before finalizing your design, check our filament range and consider a reliable build plate to keep dimensional accuracy tight during the print.