As a slight preface, some facts to lay out that play a role in what follows: scythe blades cut using a pushing slice from right to left, the blade riding the ground on its spine. The edge is held above the ground by about 1/2" on average, the edge being roughly 14-18° included angle and the steel being low-alloy carbon steel similar to 1080. In European scythes the blade is tempered down to an average of 45 RC and the bevel maintained by peening to draw out a hollow single-beveled edge and American blades (my preferred) are an average of 58 RC and beveled by grinding equally on both sides. Honing is done with a stone making passes from heel to toe to set a forward-angled scratch pattern.
I've found that the greatest mechanism causing dulling in use is deformation of the edge, and so 2 out of 3 honing sessions (done at roughly 15 minute intervals whenever there's a noticeable drop in cutting performance) that just using a oval piece of bare wood (known as a "whipping stick") to strop the edge realigns the apex without having to use an abrasive. In certain kinds of growth, different edge preparations give different results, and on some light, hard, waxy grasses like dry sparse fescues respond best to setting a coarse scratch pattern (about 200 grit) followed by a very light pass of a fine stone (about 600 grit) then stropping with the whipping stick, while very lush vegetation like young timothy, dandelions, and clover are cut best with a finer scratch pattern and overall polish. Thick grasses like mature timothy and orchard grass seem to respond best to a medium grit edge (about 320-400).
All of these edges respond better when finished off with the whipping stick, and I'm wondering if anyone has a good technical description for how this effect is being produced and if SEM or other microscope imaging has been done comparing such angular scratch patterns when finished on bare wood or coarse grits given a light pass or two from a much finer stone and then stropped on wood. I have some ideas about what's going on, but would be interested to see if photographs confirm or refute my suspicions.
You can see my use of a stone and whipping stick at the beginning of the second clip in the below video, which also serves as a good example of the results produced. When well honed I can take the top off of single fine stalks of grass with little motion.
video: [www.youtube.com]
I've found that the greatest mechanism causing dulling in use is deformation of the edge, and so 2 out of 3 honing sessions (done at roughly 15 minute intervals whenever there's a noticeable drop in cutting performance) that just using a oval piece of bare wood (known as a "whipping stick") to strop the edge realigns the apex without having to use an abrasive. In certain kinds of growth, different edge preparations give different results, and on some light, hard, waxy grasses like dry sparse fescues respond best to setting a coarse scratch pattern (about 200 grit) followed by a very light pass of a fine stone (about 600 grit) then stropping with the whipping stick, while very lush vegetation like young timothy, dandelions, and clover are cut best with a finer scratch pattern and overall polish. Thick grasses like mature timothy and orchard grass seem to respond best to a medium grit edge (about 320-400).
All of these edges respond better when finished off with the whipping stick, and I'm wondering if anyone has a good technical description for how this effect is being produced and if SEM or other microscope imaging has been done comparing such angular scratch patterns when finished on bare wood or coarse grits given a light pass or two from a much finer stone and then stropped on wood. I have some ideas about what's going on, but would be interested to see if photographs confirm or refute my suspicions.
You can see my use of a stone and whipping stick at the beginning of the second clip in the below video, which also serves as a good example of the results produced. When well honed I can take the top off of single fine stalks of grass with little motion.
video: [www.youtube.com]
