wool thread dimensions, sourcing

[Steve Ashton]

To give you a little insight into commercially woven Tartan fabric.

Here is a shot of 16oz Marton Mills in the Victoria, City of Gardens Tartan. I chose this for this photo due to the white stripe. It makes the Sett easy to count.
This Tartan is woven with 36 warp and 36 weft per inch. This is the same that Marton Mills advertises for their Jura fabric.




The rule of thumb for comparison to WPI (Wraps Per Inch) is that for balanced plain weave you take 1/2 the WPI, and 2/3 WPI for balanced Twill weave.
If you follow the rule of thumb this would give you a yarn that is about 24/2.

Here are some weaving yarns showing the WPI (Wraps Per Inch).

The Brown on the left is 40/2 in Linen. It measures at 60 WPI.

The Blue on the right is 18/2 in Wool and this yarn is 42 WPI.