The weight of a thread is how we measure the thickness of a thread. There are several different systems threads are measured by across the world as well as the different fibres, this makes identifying thread weights very confusing.
One spool of thread may be stamped No. 50, another spool may be stamped 50wt., and another may be stamped 50/3. All three of these threads are measured using different standards and are not comparable.
Where we can, we have provided TEX sizes for each thread we stock. TEX measures all threads with one simple, consistent measurement system.
The higher the number the thicker the thread; the same as machine needles.
We hope this will help you and make it easier for you to make an informed choice for you to come to an informed and ultimately successful choice for your project. We have a pdf leaflet that you can download with lots of information on threads. Click Here