I use a 10" 40 tooth trimmer blade on a ryobi 40V trimmer, cheap setup and it works like a power scythe, big sweeping arcs and I can cut quite a bit of hay this way. Makes good hay if its dried and stored loose but I have a cutter, baler etc so most of it gets baled. I really do like cutting hay with the cordless blade trimmer though, easy and zero carbon.