Heat Set Insert Rig
Summer 2023


Heat-set inserts are one of the best ways to add metal threads to thermoplastic 3D-printed parts. They can be applied as easily as using a normal soldering iron, but having a custom rig can make a huge difference in precision and repeatability. There are existing DIY design guides (such as this one from Adafruit) on how to make a simple rig, as well as pre-made packages available for everyone to purchase.

After building a replica of Adafruit's design, I thought it might be fun to build my own version for improved rigidity and build quality, as well as some added functionalities for better usability.

Adafruit's DIY heat-set insert rig (left) versus my design (right)

Details

The key upgrade I made to my design is that I changed the roller carriage design into a high-precision linear rail system. I stacked two identical sliding blocks next to each other, hoping that this could further reduce the amount of play in the sliding system. I also increased the material thickness of the 3D-printed clamping arm for rigidity.

Compared to the clever counterweight design to prevent the soldering iron from falling own on its own, I decided to try something a little unconventional. I ended up using a heavy-duty retractable badge holder on top of the linear rail.

Counterweight design from Adafruit (left) versus my design

Other design details worth mentioning include:

  1. Wooden handle for better control
  2. Tight-tolerance aluminum plate as the base
  3. Built-in magnetic storage boxes for organizing the heat-set inserts
  4. Timer outlet to prevent over-heating from prolonged usage
  5. Swappable heat-set insert tips (from Amazon)

Built-in magnetic storage boxes for inserts

Swappable heat-set insert tips (from Amazon)