Cutting rings for riveted maille
After the coils have been wound, the next step is to cut the rings from the coil. There are basically 3 different mechanical methods of cutting rings from a coil. The image below shows examples of 3 types of cutters. From top to bottom we have:
Sawing cutters are generally slow, and with the case of cut-off wheels, also tend to consume the tool rapidly.
The following two images (click to enlarge them) show the results of a flush cut before flattening:
And these two pictures show what the overlap area looks like after flattening:
Pinching cutters are slow and make poor cuts for butted maille, but have an advantage in that they generally take little hand effort.
But as it turns out, the pinching style of cut also produces the most authentic looking overlap for riveted maille, which indicates to me that it is likely that the medieval maille maker used some kind of pinching cutter.
For the butted maille maker, shearing cutters are often found to give the best trade-off between speed and quality of cut. The quality of the cut usually depends on the thickness of the wire being cut.
For riveted maille, the wire used is generally quite thin, and consequently the cut is very flush. The cut is so flush, in fact, that it doesn't look much like what is seen in authentic samples.
The picture below shows authentic riveted rings. Notice how the end of the wire tapers very gradually. This indicates that the wire was not cut very flush at all. I believe some kind of pinching cutter was used to cut these rings.