Hi there! Just repositioning some old wires along the garden wall, twisted wire strands about 3mm thick. I noticed it has a cord/string running in the twist and I wondered why. Is it something to do with the way it is made or some way of relieving stress from expansion and contraction?
The centre core of a wire rope can be fibre or steel stranded, depends on what the rope will be used for, slings, lifting, rigging,guardrail,etc. http://www.pdqwire.co.uk/info.asp