Review on [initeq] M3-0.5 Threaded Heat Set Inserts for 3D 🔩 Printing (50, Short): Enhance Your 3D Printing Experience with Premium Inserts by Todd Stepp

I chose size M3 and made holes 5mm wide and 8mm deep in PLA. I ended up ordering some Virtjoule soldering iron tips to insert, but they don't require it. I run the soldering iron at around 700F and they slowly go in very smoothly without melting too much. They take a few minutes to cool down and so far they've all been very tight without feeling like they're getting loose. The only advice I can really give is don't force them in, if they get hot enough they will push in with some pressure. Also try to keep them level when inserting as you will find that your screws need a slight angle to insert. I was very impressed with how they look fresh out of the box.