Tried a new hoof knife sharpening angle on a tough quarter crack case.

Had a big Percheron with a nasty quarter crack. Owner said three other farriers couldn't get it to hold. I usually sharpen my knives at a 25 degree angle. Decided to try a sharper 20 degree bevel for a cleaner cut on the hoof wall. Thing was like a razor. Sliced through the dead horn like butter. But on the third pass, the tip just snapped off. Clean break. Cost me a $45 knife and a lot of time. Learned that super sharp isn't always better on dense, stressed hoof material. It cut too well and couldn't handle the pressure. Had to finish the job with my old backup knife. Anyone else have a sharpening angle that backfired on a hard case?

3 comments

3 Comments

eva_adams6812d ago

That 5 degree change from your usual 25 to 20 is a huge jump in edge geometry. I've found on those big draft horse feet, the sheer mass creates a different kind of leverage on the blade. Did you notice if the tip broke while you were pulling the cut, or was it when you hit a harder spot of packed laminae?

cole99412d ago

Was it more of a twisting force that got it? I read an article by a farrier who works on Percherons, and he said the big thing with wide feet is the blade can bind in the cut if you're not dead straight. He talked about the side walls pushing on the blade, almost like pinching it. That lateral pressure on a thinner 20 degree edge might explain a clean snap right at the tip.

joseph_ellis854d ago

Wait, are we sure the angle is the main problem here? I've seen blades snap at all kinds of angles on tough feet. Couldn't it just be a flaw in that specific piece of steel? A tiny crack you can't even see would cause a clean break under normal pressure, no matter if it's 20 or 25 degrees. Maybe the tool just had a bad day.