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.

When people are designing lightweight products, or repairing a worn-out thread, a dependable fastening tool can make a big difference. This is where self tapping threaded inserts can come into play.

Inserts are classified as two general types: those held in place by external threads and those that use some means other than threads (knurls, grooves, interference fit) for their holding power.