There are several systems and all are based on the principle of relating weight and length. Direct systems give the weight of a fixed length of thread and are so called because the number grows the greater the thickness. On the other hand, inverse systems measure the length of a fixed weight of thread, so the number of meters increases the finer the thread.
The most common system is the one that expresses how many thousands of meters there are in a kilo. It is not a technical system, but it is simple and practical: a 40 thread means that 1 kilo of that thread measures 40,000m. This is theoretical, since a reduction of up to 10% is assumed due to shrinkage in dyeing and torsion: it actually has a little more than 36,000m.
This will depend on several factors: desired effect, productivity, costs, resistance, … Let’s see some reasoning to select the most suitable wire thickness:
Aesthetics: When you are looking for an embroidery with well-defined details, the thinnest possible threads should be used. But if what you want is a rustic or handmade look, it is preferable to choose a thicker thread.
Productivity: The thinner a thread is, the more stitches are necessary to cover a surface: where we need 1000 stitches of thread 30, we would need 1,150 stitches of a 40, or 1,300 stitches with a thread 50. On the other hand, with about 600 stitches of a thread 15 it would be enough.
Cost: The finer threads are more expensive the finer, which is for two reasons: it is more expensive to make a fine fiber and it takes much more energy to twist it. If we add that it takes more meters and machine hours to cover a surface, we come to the conclusion that everything works against threads that are too fine …
Resistance: It is intuitive that the resistance of a thread is proportional to its thickness. But resistance is not always a positive quality, because too much can increase needle breaks: resistance must be sufficient, not excessive.
Totally, to the point that the needle is chosen according to the thread to be used. The determining factor is the eye of the needle, because the thread has to pass through it without too much friction. You might think that it is convenient to use very thick needles to cover any thickness of thread, but that could damage the fabric. Extra large eye needles are available so you can use thinner needles with thick threads.
The most common is 40, to the point that many manufacturers only supply this thickness. And this is so because it is proven that it is the one with the best relationship of all the parameters explained above. On the other hand, Brildor offers the most extensive range of thicknesses on the market in polyester: PB15, PB30, PB40 and PB60. They are all linked to the same color gamut, although the PB40 is the only one available in all colors.
Visit the Embroidery Threads section of our store where you will find the full range of threads that we sell .
Not quite. A 40 wool yarn has more volume than a 40 polyester filament yarn. And since in embroidery what counts is what the thread covers, we could say that 40 wool is thicker. Once this is known, it is easy to apply a small correction factor when applying stitch density in the pecking program.
It can happen, as there are never two batches of yarn identical in color and thickness. But it will never be so much that it influences the density of the stitches.
It can also happen that different manufacturers, by using fibers from different origins, have slightly different threads even though they are labeled with the same thread number.