Fluffy fibers such as angora, dog hair and alpaca obscure the knot. Fibers such as cashmere and camel can be used as long as the yarn meets the other criteria for this knot. Because the knot is very small and is to be made from two identical parts, there is no room for slubs or even variations in diameter. It is very acceptable to use a variegated colored cord. As with all yarns, the wheel must have a orifice and hooks to accommodate the diameter of the yarn.
All cords require that the wheel have a very strong draw in tension.
High speed wheels for the initial singles is desirable but a slower speed for the plying is preferable. A lazy kate with adjustable tension on the bobbins makes the plying easier. Even better, if you have a tension box available use it for keeping the over twisted singles smooth for plying. The lazy kate or the tension box needs to be mounted solid.