Hi everyone I'm new here and as I've just been sharpening my Stihl HL 75 with a flat file , I thought I'd ask you all how you sharpen your hedge trimmers? I have five Echo's and the Stihl. I burn up two to four 12v Stihl chainsaw grinders a year depending how much I use the machines, (they heat up and die) witch is a lot right now, really, Does a "Dremmel" work? How bout a stone thing with a well powered cordless drill? And then, battery life? What do you all have to say?