Speaking of cordmaking, there's another technique that I've seen bandied about by some people in the SCA and certain reenactment communities --"Viking" whipcording. This is a technique where you fasten wooden bobbins to four lengths of string. The strings are then suspended from a hook or other convenient point above the workers' heads, and the bobbins are interchanged in patterns to braid the cord. This site explains the technique and shows photographs of the sorts of cord that can be produced by this method. It is possible, I'm told, to do whipcording alone, but the process goes faster if two people work together, swapping the bobbins back and forth between themselves.
Certainly this is a technology that *could* have been implemented in the Viking age; all you would need are four "bobbins" or similar long, bowling-pin like weights, string, and people-power. But the fact that a people *could* have used a particular technology isn't proof that they *did*. I've heard any number of people refer to the process as "Viking Whipcording", but those people don't point to the finding of bobbins in graves or any other support for the use of this technique in Viking age Scandinavia.
Lacking further information, I note that what we do know of Viking technology--their shipbuilding and metal working, say--indicates that the Vikings preferred simple, elegant solutions to technical problems. If I had to bet on whether Vikings would make cord with a small device that would allow one person to make cord quickly, such as a lucet or spool knitter, or with four wooden bobbins hanging by their strings from the ceiling, my money's on the lucet.
Of course, it's always possible there's evidence for the use of whipcording with bobbins of which I'm unaware. If any of my readers know of any, I hope they will enlighten me.