Weaving and unraveling ropes and wicks:
Biblically: One who weaves ropes of any type of material is liable for [the] tying [prohibition]. The amount [needed to be tied] to be Biblically liable is to the point that the rope can last with its weaving without needing to be tied at its end, in which case the work done to it is lasting.
Rabbinically: However Rabinically it is forbidden to [weave it] any amount.
Unraveling: Similarly one who separates a wick is liable for untying and its measurement is like that of one who weaves it, although [this liability is only applicable] as long as he did not intend to destroy [the wick], as all those that destroy are Biblically exempt although it is Rabinically forbidden to be done.
Summary: Weaving and unraveling ropes and wicks:
Biblically: It is Biblically forbidden to ravel threads together to the point that they can last without needing to be tied at their ends.
Rabbinically: It is Rabbinically forbidden to ravel threads in any situation.
Unraveling: It is forbidden to unravel all ropes and wicks and the like. However one who does so is only Biblically liable if a) The rope would have been Biblically forbidden to make and b) One made it with intent to rewind the rope.