I have some of these little threaded things. I have not had time to work on the project I bought them for but I intend to also build a 3d-printed rig that holds a fire-starter soldering iron so the heated tip the thread inserts come with can be used sort of like a press when heated to insert them into the print. Archive: https://archive.today/ahVoT From the post: >>Adding threads to your 3D prints is a life-changing feature, but obviously there are a lot of trade-offs and considerations when deciding on how to go about this exactly. Between self-tapping screws, printed threads, heat inserts and a dozen other options it can be tough to decide what to go with. In a recent video [Thomas Sanladerer] runs through a few of these options, including some less common ones, and what he personally thinks of them.