would anyone be interested in starting a separate stack exchange for knitters/crocheters? I don't mind being in A&C but I think there are enough knitters/crocheters and questions to form our own group.
It's a bad idea and would be rejected immediately. We had a similar proposal on Pets.SE a while back where a user wanted to seperate questions concerning cats and dogs from other, less common pets.
The problem is that, depending on how you define different categories, you end up with an infinite number of Stack sites and the distinction between them gets more and more blurry. Knitting is a craft using yarn. So are crocheting, lace-making, stitching, sewing, felting, making yarn bowls, pompoms and temari balls and countless others. If a user has a question about an exotic craft or DIY idea including yarn, where are they supposed to post their question?
New sites are proposed at https://area51.stackexchange.com/. The FAQ for new sites states:
In general, if a site makes sense as part of a bigger site, it's better to have one big site than a bunch of little niche sites. Site X should be subsumed by site Y if:
- Almost all X questions are on-topic for site Y
- If Y already exists, it already has a tag for X, and nobody is complaining
- You're not creating such a big group that you don't have enough experts to answer all possible questions
- There's a high probability that users of site Y would enjoy seeing the occasional question about X
Additionally, Stack sites are rated by criteria like questions per day, proportion of answered to unanswered questions and number of answers per question.
10 questions per day on average is a healthy beta, 5 questions or fewer per day needs some work.
The current Beta status of Arts & Crafts.SE (as of 2019-08-01) lists only 1.2 questions per day. Every question about knitting and crocheting is on topic on Arts & Creafts.SE, so not only would you create a redundant Stack site, you would also damage the existing site by reducing the number of questions asked.