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Edge deflection?
- Thread starter effenoam
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Depending on how severe or large the deflection is, a tool that works to realign edges might handle it.
Examples:
----> a smooth (polished) honing steel designed for kitchen knives. These generally work great for lightly rolled/deflected edges on fairly ductile stainless steels.
----> any steel rod could be used this way, like the smooth kitchen steel. Round shank of a screwdriver or socket wrench extension, for example.
----> the edge of a car window - that edge will usually be somewhat rounded and smooth
----> a fine/uf ceramic rod - being ceramic, it will also remove some metal. But it can also work like the smooth kitchen steel, to align the edge again.
Might also be able to 'strop' the edge on something hard, flat & smooth, like plate glass or flat, polished stone or ceramic tile. If the deflection is pretty large, this might be the avenue to take, using some pressure to bend the edge straight again from either side.
All the above assumes the steel used for the blade is ductile enough to bend straight again. Being that it's already bent out of alignment, it should be ductle enough. There's still the possibility the edge might be weakened after all the bending. So, even after realigning it, some additional sharpening might be needed to gradually take off the weaker steel, done over some time with several resharpenings.
Examples:
----> a smooth (polished) honing steel designed for kitchen knives. These generally work great for lightly rolled/deflected edges on fairly ductile stainless steels.
----> any steel rod could be used this way, like the smooth kitchen steel. Round shank of a screwdriver or socket wrench extension, for example.
----> the edge of a car window - that edge will usually be somewhat rounded and smooth
----> a fine/uf ceramic rod - being ceramic, it will also remove some metal. But it can also work like the smooth kitchen steel, to align the edge again.
Might also be able to 'strop' the edge on something hard, flat & smooth, like plate glass or flat, polished stone or ceramic tile. If the deflection is pretty large, this might be the avenue to take, using some pressure to bend the edge straight again from either side.
All the above assumes the steel used for the blade is ductile enough to bend straight again. Being that it's already bent out of alignment, it should be ductle enough. There's still the possibility the edge might be weakened after all the bending. So, even after realigning it, some additional sharpening might be needed to gradually take off the weaker steel, done over some time with several resharpenings.
Last edited:
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Can you show us a photo??
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If I understand correctly you are talking about a wave in the blade that is past the sharpened edge and is slightly into the main bevel. If that is correct you should probably just let it be, I very(very) carefully attempted to correct a similar deformation and snapped a 1/4" deep half moon out of the blade.
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Not really, it's hard to see in person much less on camera.
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That's kinda what I figured, thanks.
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Sometimes the camera sees things our eyes miss.
As Obsessed said, it really depends on the size of the deflection. A macro shot should show it clearly. Describing it as "a small portion of the edge" isn't specific enough a description. Can you measure it? At least the length?
If it's really small -- maybe a mm or two and doesn't extend more than half way up the bevel -- you can use one of the methods that Obsessed mentioned. If it's a larger half moon a quarter inch deep like Brain said, the edge is too damaged. You might be able to find a workaround to get by, but you'd be better off with a new blade.
If it's really small -- maybe a mm or two and doesn't extend more than half way up the bevel -- you can use one of the methods that Obsessed mentioned. If it's a larger half moon a quarter inch deep like Brain said, the edge is too damaged. You might be able to find a workaround to get by, but you'd be better off with a new blade.
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I actually missed his whole post, but this is the best pic I could get. I think I'm just not gonna worry about it.
Thanks for the photo.
I think I see it, but it is small and difficult to tell how severe it is from this angle.
If it were me, I'd steel it and then use a guided system to put a clean, even angle on the entire edge. After that, use it and sharpen it as you usually would, and I'd guess it will be fine. It might be hard to get a burr off the convex side of the deflection, but that should not cause too much of a problem.
I think I see it, but it is small and difficult to tell how severe it is from this angle.
If it were me, I'd steel it and then use a guided system to put a clean, even angle on the entire edge. After that, use it and sharpen it as you usually would, and I'd guess it will be fine. It might be hard to get a burr off the convex side of the deflection, but that should not cause too much of a problem.
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That looks fairly minor, as compared to what I'd pictured in my own mind. Blade appears to be relatively thin(?), maybe thin enough to gradually straighten it out over time. If it were mine, I'd probably approach it from a strategy of laying the blade flush near the edge of a smooth, hard surface, like glass or stone (or tile), and give it a few relatively firm stropping passes (edge-trailing, in other words) along & over the edge of that hard surface, just to see how it responds. Maybe place a sheet of paper or fabric in between the two, to avoid scratching the blade. Nothing too firm with pressure used, but just enough to see if the deflection will gradually realign. Otherwise, it seems minor enough that I wouldn't push it too far, in trying to make it look perfect again.
If you can sharpen it so the edge will slice easily & smoothly into the edge of a piece of paper, through the full length of the deflected area without snagging, that would tell me there's not too much to worry about. I'd pictured a deflection more severe, one which would get in the way of smooth cutting. But, it doesn't seem to look quite that bad.
If you can sharpen it so the edge will slice easily & smoothly into the edge of a piece of paper, through the full length of the deflected area without snagging, that would tell me there's not too much to worry about. I'd pictured a deflection more severe, one which would get in the way of smooth cutting. But, it doesn't seem to look quite that bad.
Good luck. Do the steeling first. Then sharpening. Last, do stropping. Stropping will do nothing at this stage. It just refines an already sharp edge.
Not sure what the blacksmith will do. You really can't bend it back into shape without weakening the edge.
In the future, you might want a blade in a tough steel with a higher Rc (which is a proxy for strength, or the ability to resist bends, deflections and rolling).