Making a strand with a core

Most, if not all the rope made in Japan seem to be constructed this way. The strands of such ropes are made of yarns twisted around 1 or 2 central core yarns. As the core yarns are not affected by the twisting, they are always shorter than the outer yarns. Their function is to provide a physical axis around which the outer yarns lay parallel to one another, forming a virtual ribbon of yarns wrapped around the central axis.

While it is very easy for industrial machines to produce that type of strand, making it using a rope-walk is not as easy a process, as you need to find a way to keep the core yarn in the center of the strand and make sure it doesn’t get caught in the twisting of the outer yarns. Registering the yarns with a plate or similar device may help, but you’ll have to make sure that the core yarn doesn’t sag in the middle, due to the length of yarn used.

My personal workaround is to use either a rayon or polyester twine for the core, and jute, flax or hemp for the outer yarns. The slight elasticity of the rayon or polyester allows to stretch it just enough so that it will naturally place itself in the center of the strand without any interference on the outer yarns.

To go back to “Steps”, click here

Next Step: Laying the rope, click here

Making a core-less strand

This is the type of rope made with traditional rope-making machine: a certain number of yarns are bunched together, and twisted under tension, as shown below. To make the structure easier to see, 2 of the 12 yarns are black.

The yarns are stretched and ready to be twisted into a strand.

The strand is then twisted under constant tension. This time, the black yarns are positioned at the centre of the strand, and are thus completely covered by the other yarns.

The 3 strands are then counter-twisted together to lay the rope. The black yarns are still invisible, as they were already hidden inside the individual strands.

What’s the difference between both constructions? See here