After many hours of mowing and honing, the metal at the edge gets worn back to where the metal is thicker. At this point the whetstone will no longer be able to restore the acute, penetrating angle required for a sharp edge. To resharpen your blade, you will need to hammer the cutting edge, to draw out and thin the metal at the edge, until it is thin enough for the whetstone to be effective again. There are many different styles of peening; not just one. The peening technique that I personally prefer and recommend, is described in my original 1SR Peening Manuals. They are available on this page as documents, and can be viewed or downloaded below:
1. Peening an Austrian Scythe Blade on a Narrow Anvil
If you are not a member of Scribd, you can download my first manual here:
To make peening on a narrow anvil even easier, I developed the 1SR Roll-Guide. It can be quickly adjusted while you are peening, with just a couple of taps with the hammer, and it rolls and does not dull the edge of the blade.
If you are not a member of Scribd, you can download my 2nd manual here:
Special Note for Bush Blades: It is not recommended that beginners peen their bush blades. You risk creating too weak an edge profile for cutting woody stems. Instead, sharpen by first honing them with a fairly coarse artificial whetstone, or a fine mill file or diamond file, followed by a scythe whetstone. Bush blades are also honed at a slightly steeper angle than a grass blade. Hone the bush blade in the field, as you would the grass blade, but at a slightly steeper angle. When the bush blade needs sharpening, hone it as in this video, but with a coarse artificial stone, followed by a medium grit natural stone. If you can imagine a spectrum of edges, with a razorblade at one end, and a hatchet at the other; the grass blade would be closer to the razor, and the bush blade would be a bit closer to the hatchet. So the edges are treated and shaped accordingly.