If you hand spin to knit (or even to sell), then the term 'Warps per Inch' comes up a lot in the books you read. So what is it? Well, it is a method for classifying the 'yarn' weight of your finished yarn (lace, fingering, double-knit and so on.)
There are may different tools you can buy, I supply one that Ashford make in my shop. These are always handy to keep with your wheel, or like the one I supply on a key chain. You can however, use a ruler if that's what you have to hand.
Take your yarn and select the middle section, which is usually more consistent than either end. Start by wrapping the yarn around the inch measurement, starting at the beginning and moving slowly towards the inch mark (this is called 'warping'). Your yarn must lie flat against the measurement and not overlap its sister warp. It should also be not too tight or too loose. When you have finished count how many warps of yarn you have.
Use the chart below to check what yarn weight you have made... so for example; if you have 12wpi, then you have created a fine yarn, that may be classified in the US as 'Sport', or in the UK, NZ and AU as '5ply' (or 'Light Double Knit', if you reference a Yarn Weight Conversion Chart).
By working out your yarn's WPI, you can then work on calculating which knitting needle size to use.
Wraps per inch (WPI) Conversion Chart, or (2.5cm if you are metric!)
|Standard Yarn Weight System||Yarn Type (US)||Ply (UK, NZ, AU)||Wraps Per Inch (WPI)|
|0 or Lace||Thread, Cobweb and Lace||1 - 3 ply||18+ wpi|
|1 or Superfine||Fingering||4 ply||14 wpi|
|2 or Fine||Sport||5 ply||12 wpi|
|3 or Light||DK||8 ply||11 wpi|
|4 or Medium||Worsted||10 ply||9 wpi|
|4 or Medium||Aran||10 ply||8 wpi|
|5 or Bulky||Bulky||12 ply||7 wpi|
|6 or Super Bulky||Super Bulky||5-6 wpi|
Information sourced from http://en.wikipedia.org/wiki/Yarn_weight#International_yarn_weight_conversion
Find your supplies at www.SarasTextureCrafts.com
Have a wonderful day... Sara x