The best fabrics for chainstitch embroidery are woven fabrics like denim, canvas, and felt. The needle of chainstitch machines is larger and can leave holes in knit fabric that grows over time. Because of this, we only embroider our Daily Disco brand sweatshirts because we know the fabric handles chainstitch well and holds up well through washes. For fabrics like leather, we do not stitch directly onto it but we can create large back patches that we attach to the leather jacket. Email us for reference photos of this! info@dailydisco.com