For most applications little more than a call out tag with the respective thread details is needed when designing and detailing part drawings. Sometimes, however, the devil is in the details and things such as threaded surfaces can make or break a finish rendered part. Of course you can use a helical cut to design in your own threads when making a part, but that can be time consuming. Recently I was working on a design using extruded aluminum profiles and I needed one end of a few pieces tapped to an M8x1.25 thread. Because the extruded aluminum already has a hole through it, it seemed redundant to make a hole callout putting the same size hole on top of the existing hole. Not only that, but in my drawing it doesn't really do it justice for the guy that was going to make the part and it would be easy to "accidentally" tap the wrong end. Since my finish model already had the bolt that would go into the threaded hole in it, I quickly thought, hey.. why dont I just do a boolean subtract and use the actual bolt model (courtesy of McMaster-Carr) to create the actual thread detail. It was as simple as pressing the boolean subtract button, constraining the bolt in the extrusion, and checking the green check mark. Simple and good looking thread detail.