I finally have learned what the correct process and file is to sharpen my Fanno pole saw blade. There is an eBay seller in Oregon that sells the Silky 200mm feather files as shown in your video. I took my time and re-watched portions of this video to make sure I got the technique down, including the short ramps to minimize drag on the push (upward) stroke and of course, create the perfect cutting edge for the pull (downward) stroke. I tested the sharpened saw this afternoon on some black walnut and ash limbs and the ease of cutting was amazing. No more dull saws at my place. Thank you! The only suggestion I could make is to re-film this video again at a higher resolution to make the tooth detail easier to see.