Our wrap per inch guage has the dual purpose of being a orifice hook as well. The orifice hook is made from stainless steel, so it will not rust.
WPI stands for “wraps per inch,” and is a way to measure the grist, or thickness, of a yarn. This is a particularly useful measurement if you are substituting one brand of yarn for another that is called for in a pattern, or if you are substituting handspun yarn, of course!
To measure WPI, start by wrapping the yarn around either the half inch or inch space on the guage. Continue wrapping around until you get to the end of the space, then count how many times you wrapped around in that space (if using the half inch space double the amount of wraps). It comes with a chart to help as a guide.
If you check your WPI periodically while spinning, you can adjust to keep the grist of your yarn even.