The short answer: most orthodox jews would not consider the tzitzit strings I spin kosher because they would not consider me Jewish. More detail below.
Firstly, huge thanks and shout out to Ghost of Fury Wren, who encouraged me and helped answer some questions when I started working towards making tzitzit strings, and who maintains a very helpful info page with lots of links to sources and further information. If you are looking for tzitzit strings in bright or custom color schemes, I recommend their work.
The longer answer: I am a Jewish convert, and the rabbis who oversaw my conversion are primarily affiliated with the reconstructionist movement. I also do not keep shabbat in accordance with traditional halacha. In future I hope to expand this page with links to sources in traditional Jewish texts, but for now here are some of the considerations I make around the halacha of creating tzitzit strings:
Here are some additional considerations I make that are not strictly required by halacha:
My latest batch of tzitzit strings was spun with corriedale wool from Aker Fiber Farm. This is a small fiber farm based in the US where the sheep live very comfortable lives with access to open pasture. When their wool grows long enough they are shorn (a process that is safe, and necessary for the health of the sheep) and then the fleeces are processed into clean, combed fiber at a mill before I buy the fiber to spin. Corriedale sheep are a breed raised in many farms across the US, and they do not require procedures like mulesing to stay healthy. I will update this page if I spin tzitzit strings using wool from a different source in the future.
I use an electric spinning wheel to spin yarn because my disabilities mean I am unable to treadle a more traditional spinning wheel without injury. It is a fantastic adaptation that has allowed me to continue making yarn even when I have had to stop participating in other crafts due to their impact on my health. Before beginning to create tzitzit strings I made sure to check if this could affect the kosher status of the strings I spin. Luckily, it does not. Here’s a summary of how I came to that conclusion:
There is some debate among rabbis about tzitzit strings that are “machine spun”. The debate is about whether a Jewish person setting up and turning on industrial equipment that spins yarn automatically fulfills the requirement that tzitzit strings be created with the intention to fulfill the mitzvah of tzitzit. My electric spinning wheel does not spin yarn automatically, so whatever position you take on this debate, it is not relevant to the strings I make.
Without getting too technical, most spinning wheels used for hand spinning today require the spinner to do two things at once: treadle and draft. Spinners treadle with their feet to keep the main wheel of the spinning wheel turning. This is the part that my electric spinning wheel does for me, using a simple motor. Drafting is the process that spinners do with their hands to control the fiber as the motion of the wheel creates twist and winds the newly created yarn onto the bobbin. I do this part of the process exactly the same way as spinners using traditional spinning wheels. This means that every millimeter of thread that makes up the tzitzit strings I create passes between my fingers at the very moment the fibers are twisted together, becoming yarn.