Balsa wooden has been one which I've been seeing a lot with this machine. Do not bend your arms up not one tiny bit. But don't bend your arms. https://Products-DD.Com/category/%e0%b9%80%e0%b8%84%e0%b8%a3%e0%b8%b7%e0%b9%88%e0%b8%ad%e0%b8%87%e0%b8%9f%e0%b8%ad%e0%b8%81%e0%b8%ad%e0%b8%b2%e0%b8%81%e0%b8%b2%e0%b8%a8/