Just want to say that the idea is not mine, a wonderful seller shared it with me in a yarn shop. Though, the primary source was neither the seller, but I'm very grateful for this promotion, so to say, to the masses. Remember her question "Do you know how to knit in three threads with the same ball?" which brought me completely at a loss. In two threads — yes, I seem to be able to do it, but in three... "Is that possible?", I asked. And then the miracle was demostrated — surprise and admiration came to me, as the brilliant way turned to be very simple. Maybe this will be a revelation for you ;) you see, it was not always possible to find a yarn with the desired thickness, especially if it's some small item or detail. And then — ta-dam!

So...

1. Pull a long thread tail and fold it three times (I used a short thread in the photo to room it).

2. Knit the blank until the end of the triple thread.

3. When there is a little tail left, pull the working thread through the loop to the required length.

And... Voila! You have a triple thread again!

Then repeat all.

I used this method when crocheting, but I suppose that it will do with knitting needles, too.

Maybe someone has already shared this method, but I unfortunately have not seen it. But as people say, practice makes perfect!