What difference does it make?

I finished carving my spindle shaft to match the dimensions of the shaft found in Ribe, and I have been testing it against the shaft I carved to be similar to the shafts found in Greenland. Serendipitously, the Ribe shaft weighs the same as the Greenland shaft, and is the same length. Since I am using the same whorl on each shaft, the only difference between the two spindles is the distribution of mass along the shaft.

The Greenland style shaft is on the top, the Ribe style shaft on the bottom. The total weight of each spindle is 29 grams.

I spun with each spindle, first using Shetland wool, and again using Finn wool. I set the wool and let it dry without stretching it. When I spun, I did not add additional twist to the spindle until it had stopped spinning. Here are my results:

Greenland shaft/Shetland wool: 14 wraps per cm/63 degree angle of twist

Ribe shaft/Shetland wool: 14 wpc/66 degree angle of twist

Greenland shaft/Finn wool: 13 wpc/59 degree angle of twist

Ribe shaft/Finn wool: 12 wpc/61 degree angle of twist  

I am not completely confident in my angle measurements of the Finn thread. While I can see the twist in the white wool, it is difficult to measure it accurately. The Shetland wool has variation in the color of the fibers, making it much easier to measure.

As part of my spinning study in 2011 I tested the Greenland style shaft against an equally long straight shaft. Then I found that the Greenland shaft produced an angle of twist of 62 degrees, and the straight shaft produced an angle of twist of 53 degrees, both using Shetland wool.

So, was the shape of the spindle just a matter of personal preference, or did experience show people that a different shape could have a positive impact on the final product? Clearly this is not enough spinning to make an educated guess, but it does make me wonder.