Adafruit Industries Adafruit Industries Heat Set Insert for Soldering Irons #4-40/M3
If you have tried to set heat-set inserts in your plastic or 3D printed part with your soldering iron, you may have had the frustration of pushing the insert in only to have it come right back out stuck to your soldering iron and ruining your part in the process. Most soldering iron tips can catch on the rim of the insert causing it to stick on the iron when you pull the iron out. If you use the "horizontal method" it's hard to know the insert is straight. These insert tips from Virtjoule have a vertical wall that solves that problem. The iron pulls right out after pressing the hot insert. Because the shoulder is square it's easier to know if the insert is square in the piece, something that's harder to control with a conical soldering tip.
Adafruit Industries Heat Set Insert for Soldering Irons #4-40/M3