Norse measurements and units are non-standardized and ambiguous, and as Christie Ward notes, seem to be oriented more toward larger measures. For more on this, see Gary Anderson’s interpretation or Christie’s own. We know more of Anglo-Saxon measurements.
These give you an idea of how the folk in the Viking Age divided lengths. Keep in mind that there was no zero at the time.
In Britain, at some point, the ell was standardized, possibly by Edward I in the thirteenth century. He commanded that each English town should have an ell-stick, which were all cut to the same length. This indicates to me that such straight-edges were used during the time before measurements were standardized. The ellstick (also known as an ell-wand, a mete-wand or merely as a Stikke) is a bar of wood or metal that is about an ell in length.
References to rules, squares and compasses for woodworkers are not found, but it would appear that such items were known in the Viking Age. These were instruments used by masons in the construction of buildings, although it takes little imagination to know that at least the better educated woodworker knew about them as well.
Such instruments were known to have existed in Roman times, and some from that era are still extant. They were made out of bronze, since the Mediterranean world was fairly iron-poor; by the middle ages in northern Europe, where, iron was more plentiful, the instruments were generally made out of iron. In the sixth century, Isidore of Seville refers “to a compass as a pair of dividers, perhaps not unlike those already noted in Roman times. Theophilus, twelfth-century author of the Schedula diversarum artium, mentions the use of a compass in making a small silver cup.” He also remarks about iron dividers and calipers, which is a big difference from the bronze ones used by the Romans.
Both squares and straight-edges are described by Isidore of Sevile: “It is constructed out of three rules, of which two are two feet long, and the third is two feet and ten inches long. They are…joined together at the ends of each to form a triangle.” This description indicates that medieval folk knew about the square, and the casual use of “rule” probably indicates that straight edges were well known as well.
This blog entry is theoretical and highly speculative. We have a strong suspicion that woodworkers of the time used items similar to these to measure their projects, so we wouldn’t object to woodworkers of today using such devices on the line. The fact that neither a wand nor a square was included in the Mästermyr chest certainly indicates that not all woodworkers of the era would have used them, though I suspect that a few might and certainly encourage modern woodworkers to use one. I would suggest that if you want to use a stick to take a piece of hard wood or metal that is about two feet or an ell in length. Divide it into lengths that fit your purposes: inches, millimeters, finger widths or anything else that is useful. Mark these with scratches, with knife notches or with pyrographic marks. If legends are needed, they can be given those like that you see on later runesticks
The resulting stick can be used in your efforts and may be displayed at events with no problem.
For a note on later medieval rules and squares used by woodworkers, see the Saint Thomas Guild of Woodworkers.