yes- the higher the wt the finer the thread- 100 wt thread (often silk or monofilament) is very fine thread- 12 wt thread is almost string. often people doing general sewing/piecing use a 40-60 wt thread- 30 wt may be used for heavy sewing (making denim pants) heavier wt threads are used for home dec projects and some decorative applications. some of us use 60-100 wt threads most of the time. for more information on threads visit 'Superior Threads' they have charts showing the different types of threads, their different weights, what they are best used for and what needles to use with them- it is important to use the correct size/type of needle for the different types/weights of threads so you avoid fraying/breaking threads. as for the 'Star Thread' I've used star threads a few times- not for piecing - but for some general sewing/ kids clothes, purses/totes. my (most used) machine does not like it- but my old vintage Singers accept it ok.