We have all done it, overtightened a bolt and blown out the threads. When a bolt starts to tighten up and then go suddenly loose, you know that the threads are toast and now you have a problem.

We’ve all had this happen at some point while tightening hardware: It feels like it’s snugging up nicely, and then it suddenly seems to tun too easily. Or maybe you were removing stubborn hardware and ...

This article was updated May 25, 2023. It was originally published Nov. 17, 2009. To put hard, durable threaded holes in plastics, engineers often specify threaded metal inserts that will securely ...