The original Herjolfsnes 41 garment has 26 cm slits up the lower sleeves with 16 fabric buttons, spaced about 1.5 cm apart (Ostergard, 2009). Hold onto your hats because the buttonhole sides of the slits are not hemmed! However, the twill fabric of these edges was ingeniously engineered with reinforcing, which include:
— singling stitches, serpentined up the length of the buttonhole region, spaced every couple of weft threads
— a twisted cord attached directly to the unfinished edge (Ostergard has commented that this cord is "possibly attached with the stitches that form the singling." However, so little of the preserved cord remains on the original garment that she could not be certain.
From photographs in WitE, it appears as though the buttonholes on the original sleeve are just a few mm from the edge, and the slits themselves are noted to be 7-10 mm in length. Ostergard also wrote that the original reinforcing singling stitches only extend about 8 mm in from the edge. That means that they only reinforce the half of the buttonholes next to the edge.
I began my lower sleeves by marking off with contrasting wool yarn the placement of 14 buttonholes (this is the number that fit comfortably on my gown from the cuff to the elbow spaced at 15 mm). Since my fabric is tabby and not as naturally thick nor as tightly woven as the original garments, I decided to extend the singling stitches past the buttonholes, so that the entire area was reinforced. I found that by having the buttonholes marked before I made the singling I could position the stitches so that I would avoid cutting them when I cut the slits.
At the same time that I was making the singling reinforcement, I was attaching a twisted cord to the unfinished edge. Each time that the singling row of stitches came to the unfinished edge, I twisted the cord and passed the yarn through the centre of the cord before turning for the next row. In this way the cord was formed and became attached to the edge as the singling was made.
Once the singling and cord were completely attached, the buttonholes could be cut and bound. Ostergard does not note if the buttonholes were bound on the original garment. However, in the photograph provided in WitE, they do appear to be bound. I decided that with the fraying nature of my handwoven cloth, I would bind around my buttonholes completely, even at the ends. I cut the slits and bound them one at a time. I made the slits about 7 mm long and once bound they measured slightly longer.
The buttons were self-stuffed: made from small circles of cloth sewn with running stitches along the circumference; drawn tightly together; flattened to make another, smaller circle; then sewn with running stitches again along new circumference; drawn in very strongly once again and sewn firmly together. They were attached directly to the hemmed sleeve edge, matching up with the buttonholes.
Ostergard, Else, Woven into the Earth: Textiles from Norse Greenland, 2nd. Ed., Aarhus University Press, 2009, pp. 167-170.