Designing and producing robot parts with 3D printers has become a reality with the advent of affordable devices like the MakerBot, but after you create the necessary parts, how can you attach them to each other in a reliable, robust way that will withstand actual use in the unforgiving real world? Our friends over at I Heart Robotics have come up with practical solution – brass inserts that install in most 3D printed plastic parts using a soldering iron. According to their tests, the insert holding strength should be more than sufficient for most applications.